COUGAR SCIENCE - Home/Lesson Plans



Forensic Science Curriculum Notes Unit 1: Overview of Forensics, Observational Skills Interrogation, Reporting, and Profiling Definition and Scope of Forensics Application of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system. 11 Sections Criminalistics Digital and multimedia sciencesEngineering scienceGeneral Jurisprudence (theory of law)Odontology Pathology and Biology Physical Anthropology Psychiatry / Behavioral Sciences Questioned Documents Toxicology CSI Effect Simplifies scientific proceduresShows CSI teams collecting evidence, processing, interrogating, carry out search warrants, etc. Creates unrealistic expectations and detracts from the courtroom. History of Forensic Science Pre 19th Century Earliest record of applying forensics was in China. Woman claimed her husband died in accidental fire. Tested by burning two pigs (one alive and one dead) to test her claim. (She was guilty.) Ash not found in the mouth. Mathieu Orfila Father of Toxicology. First to detect poisons and their effects in animals. Late 19th Century Alphonse Bertillon First to apply anthropology to a system for identifying a person. Henry GaltonPublished the first book on fingerprints and their classifications. 20th Century Karl Landsteiner Discovered blood types. (A, B, AB, O)Albert Osborn Developed the fundamental principles of document examination. Edmond Locard Became the leader for the study and research in forensic science. Developed the Locard’s exchange principle: when two objects come into contact with each other, a cross-transfer of materials occurs. Modern Advances Sir Alec Jeffries Discovered DNA typing and the first DNA profiling test. Led to the development of computerized databases on physical evidence such as fingerprints, bullet markings, and DNA. Crime Labs Oldest existing crime lab in the United States is the LA Police Department. (1932)FBI eventually organized a national laboratory offering forensic services to all agencies. (Although many have their own in their respective jurisdictions.)Drug-related arrests are the sole driving force behind the expansion of crime labs. (Requirement that drugs are sent to labs for testing and confirmation.)Four major federal crime labs that extend beyond jurisdictional boundaries:FBI in QuanticoDrug Enforcement Administration (DOJ)Bureau of Alcohol, Tobacco, Firearms, and Explosives (DOJ)U.S. Postal Inspection Service Services Three reasons why services vary between crime labs:Variation in local lawsDifferent capabilities and functions of the organization to which a lab is attachedBudgetary and staffing limitationsBasic Services Physical science unit (chemistry, physics, and geology)Biology unit (DNA, hair and fibers, botanical materials)Firearms unit Document examination unitPhotography unit Optional Services Toxicology Latent fingerprint unitPolygraph unit Voiceprint analysis unit CSI unit More specialized services Forensic pathology Forensic anthropology Forensic entomology Forensic psychiatryForensic odontologyForensic engineeringForensic computer and digital analysisFunction of the Forensic Scientist Applying the principles and techniques of the physical and natural sciences to analyze the many types of evidence. Evidence tells the story. Free of bias. Analytical skills vs deductive skills Determining Admissibility of Evidence Determined in the court case, Frye v. United StatesRuled that in order to be admitted as evidence, questioned procedure, technique, or principles must be generally accepted by a meaningful segment of the scientific community. Witnesses are considered experts if they meet the criteria:Testimony is based upon sufficient facts or dataTestimony is the product of reliable principles and methods.Witness has applied the principles and methods reliably to the facts of the case. Judging Scientific Evidence Determined in the court case, Daubert v. Merrell Dow Pharmaceuticals, Inc. Judge can determine if the evidence is sufficient using the following criteria:Whether the scientific technique or theory can be (and has been) tested. Whether the technique or theory has been subject to peer review and publication. Technique’s potential rate of error. Existence and maintenance of standards controlling the technique’s operation. Whether the scientific theory or method has attracted widespread acceptance within a relative scientific community. Held up in the court cases Kumho Tire Co., Ltd.v. Carmichael and Coppolino vs. StateExpert Testimony Expert witnesses are individuals whom the court determines to possess knowledge relevant to the trial that is not expected of the average person. Evaluate evidence when court lacks expertise to do so. Cannot render any view with 100% certainty. Only advocate the truth, and cannot pick sides. The Melendez-Diaz v. Massachusetts case confirmed the need for forensic scientists to appear in court so the defendant has a chance to cross examine. Observations Observations are the single most important skill of a forensic scientists. Perception is limited and can impact the way we view our environment. Ex: I give you a cupcake with pink frosting, what do we assume? Brain Processing of Observations Information from our sensesWhat we pay attention toPerceptionShort-term memory Long-term memory Witness Observations While key components of investigations, witness observations are some of the most faulty. Impacted by:Emotional stateAlone or in a group Number of people or animals in your areaType of activity going on around youHow much activity is going on around you. PrejudicesMemory Concentration levelInnocence Project (Assignment) Group formed to reexamine post-conviction cases using DNA evidence to provide conclusive proof of guilt or innocence. Faulty eyewitness accounts made up 87% of wrongful convictions. Mistakes included mistakes in age and facial distinctivenessFact vs Opinion are often confused. Judicial Process Bill of Rights Important to understand your rights when it comes to the judicial process. Arrest Fourth amendment protects from unreasonable search and seizure. Law enforcement must show probable cause. Four categories of evidence gather for probable cause:Observations via five sensesExpertise (gang officers may recognize gang symbols)Information Circumstantial Evidence Must convince a judge that a crime took place and there was probable cause to obtain a search or arrest warrant. Miranda rights must be read. Interrogation Techniques Basically an interrogation is a questioning session typically with an accusatory tone. Cognitive Approach Designed to enhance the person’s recollection of the details of the incident. Encourages the subject to reconstruct the circumstances surrounding the crime or incident in different ways. Goals (Examples on pg. 43 of blue book)Recall emotions or retrieve memory of surroundings. Report even the smallest details. Recall events in a different order. Alter the suspect’s or witness’s perspective. Interviewing Children Help provide a comfortable and safe environment. Questions are developed ahead of time to focus on the child. Private location with a toy or blanket. Parent or advocate is nearby. Interrogation Techniques (Videos 3 x 14 min.)Investigator reviews all statements, reports, and evidence reports. Ends if invoke right to remain silent. Interrogations cannot deny bathroom breaks, access to medication, must be videotape or write down confession, and use no force. Models of Interrogation (Chart pg. 48 blue book) Suspect Decision Making ModelOptions available are offered and the consequences of each. Cognitive-Behavioral Model Questioning continues over a period of time until the suspect is less resistant. Psychoanalytical Model Suspect is told that confessing will lift the burden of guilt and that the suspect will feel better. Emotional Model Allow suspect to shift the blame without escaping legal responsibility. Interaction Process Model Determine the best method to approach the interrogation based on the suspect’s background and history and on the facts of the case. Reporting Information Maintain objectivity which is simply reporting the facts of the case without presenting the opinion of the investigator. Reports include:Name and address of person interviewed and if they are a suspect, witness, or victimChain of custody of evidencePolice reports Lab reports Criminal Profiling History Cesare Lombroso is considered the father of criminology. Originally believed the following characteristics were indicators that a person would commit crime:Abnormal head size and shape in relation to the ethnicity. Extremely large jaw and cheekbonesLarge, pouty, pronounced lipsLong armsDiminished chin or very long, short, or flat chinAbnormal size shape of ears. **Since been disproven. States of the Profiling Process Input Begins with collecting as much information about the crime as possible using photographs, history of the victim, autopsy photos, reports, and interviews. AVOID SUSPECT LISTS to encourage no bias is present. Decision Process Models Uses decision points to compare and differentiate the information and to form a basis of the profile. Classify the Crime (arson, burglary, homicide)Single homicide (pg. 458 blue book)Double homicideTriple homicide Mass murder Killing spreeSerial murders Determining Motives Financial intent, sexually motivated, emotional motives, or serial motives that include sexual fantasies, voyeurism (spying), or sadism (torture). Risk Level Age, lifestyle, occupation, ability to resist, size, and location are used. High, medium, and low risk. Crime Assessment Completes a crime reconstruction based on the behaviors of the criminal and victim. Organized or disorganized crime scene. Identify the modus operandi or method of operation. Recognized pattern of behavior including use of tools, weapon of choice, or preference of victims. Signatures are sometimes left. Criminal Profile Developing a description of the suspect. Profiles include:Race, sex, physical characteristics, habits, and values and beliefs. Examples Arsonists are typically white males between 18-27 who are loners with a history of drug or alcohol abuse. Criminal record likely with poor employment history. Serial murderers are white males between 25-34. Least average intelligence and possess charming personalities. Older and intelligent if crime scene is organized. Likely victims of child abuse. Investigation Apprehension Victimology Study of victims affected by crime, accidents, or natural disasters. Victim Risk Low risk victimMedium risk High risk Risk Factors Aggressive, Impulsive, Anxious, Passive, Thrives on attention, self-inflecting injuries, poor self image, negative, and exhibits addictive behaviors. Assessments via Curriculum Map Unit 2: Microscopy and Forensic Techniques Crime Samples and Types of Tests Questioned vs Control Samples Questioned samples are the evidence samples while control samples are known samples used for comparison purposes. Analyze both physical and chemical properties. Presumptive and Confirmatory Tests Presumptive Tests Allow a field investigator to screen evidence to reduce the number of possibilities and to get a preliminary identification. (Luminol and blood) Confirmatory Tests These tests are done in the lab and are used to make a more specific identification. (Blood type, DNA)Forensic Techniques and Methods Microscopy In the late 1660s Robert Hooke was the first to develop microscopes capable of detecting cells. (He also termed the word cells.)Types of Microscopes Compound Light Most widely used using a light source and multiple lenses. Magnifies objects between 40x and 1,000x allowing you to view a virtual image. Total magnification is typically equal to the product of the magnifying power of the objective and eyepiece lenses. If an eyepiece and objective both have 10x magnification, the total magnification is 100x. Used to view hair, fibers, and cells. StereomicroscopeMicroscope used for larger specimens or opaque specimens. Works by reflecting light off the surface of the specimen. Produces 3D images useful for dissecting. Used often for insect larvae, paint chips, soil samples, etc. Comparison Microscope Two microscopes connected to one eyepiece. Useful for comparing bullet striations, fibers, and hair samples. Typically utilizes a known sample and questioned sample. Electron Microscope Microscope that uses a beam of electrons instead of light (like all the others) to form images. Magnifies up to 500,000x with good resolution but no color. Two typesTransmission electron microscope (TEM) passes beam of electrons through a thin slice of the specimen to analyze internal structures. Scanning electron microscope (SEM) passes a beam of electrons over the surface to produce 3D images with surface details. Used in forensics to analyze small specimens such as trace materials like gunshot residue, pollen spores, or even in forensic pathology for bacteria and/or viruses. Chromatography Technique that separates substances within a mixture based on their physical properties. Different substances will adhere to solid surfaces or dissolve in a solvent differently. Paper Chromatography Small amounts of a liquid mixture is placed near the bottom of a piece of paper and the paper is placed in a container with a little bit of solvent. Solvent moves up the paper during the mobile phase. (Paper is referred to as the stationary phase) **Different parts of the mixture adhere to the paper at different places and a pattern is left behind. (Chromatogram)Retention factor is calculated and compared to other samples do identify the mixture. Rf = Distance substance traveled / Distance solvent traveled. (no label)Forensic Use of Chromatography Analyze dyes in fibers, test for explosives or accelerants, and to check body fluids for presence of drugs. Other (more advanced) methods of Chromatography are used in Forensics Think layer chromatography (TLC): similar to paper chromatography but the stationary phase is a thin layer of gel material on a glass plate. Faster and produces clearer separations than PC. Used mainly for dyes and inks. Gas chromatography: Performed at high temperatures and is useful for separating mixtures what contain large molecules such as proteins in blood. (BAC)High performance liquid chromatography: Takes place at room temperature and mainly used for the presence of flammables. Spectroscopy A technique that relies on the phenomena that occurs when substances are heated. When heated, it will emit light at a specific wavelength. (chemical property)Used to ID fibers and other trace evidence, accelerants, and drugs. When the technique is used it will produce a spectrograph that measures the wavelengths of light emitted and captures a spectral image. (Chemical fingerprint)Different Types Mass spectroscopy is often used with gas chromatography. (Video)Sample is loaded into a mass spectrometer and vaporized and ionized forming charged particles. Particles are passed through magnetic or electric fields. The path they take depends on the ratio of its mass to its charge. Every chemical is unique. Most commonly used for confirmatory tests. Atomic absorption spectroscopy measures the amount of light of a specific wavelength absorbed by atoms of a particular substance. Useful for determining heavy-metal contaminants in air, water, and soil. Also used for analyzing paint chips. UV spectroscopy measures wavelengths of light and can be used to determine the concentration of different elements in a solution. Most often used to detect drugs in blood or urine, analyze components of dyes and food additives, or measure air and water quality. Proper Measurement Practices Math Toolbox Scientific Notation (Practice Problems in Blue Chemistry Book)Tool to represent very large or very small numbers in an easier format. Based on rules of 10 with a coefficient and an exponent (positive or negative). Example Problem1.14 pg. 35 McGraw Hill a-ePP 1.14 a-e Rules of Scientific Notation Multiplication Multiply the coefficients and add the exponents. (pg. 36)Division Divide the coefficients and subtract the exponents. (pg. 36)Addition and Subtraction Express both numbers with identical exponents. Ex pg. 36Example Problem 1.15 pg. 36 a-dPP 1.15 a-d Accuracy, Precision, and Significant Figures Measurements are either exact (counting) or not exact. Precision and Accuracy Precision is the extent of agreement between repeated measurements of a given value. Accuracy is the difference between the value of a measured number and its expected or correct value. (Diagram bullseye model) Significant Figures All the digits in a number of which we are absolutely certain, plus one additional digit that is uncertain. Ex: Say we read on the side of a graduated cylinder and the line seems like it is at 18. What are we certain on and what are we uncertain on?Rules on Determining the Number of Sig Figs Nonzero numbers are always significant. All numbers are significant when counted. A zero alone in front of a decimal point is not significant. 0.2806. A zero to the right of the decimal point but before the first nonzero digit is not significant. Ex: 0.002806. A zero between nonzero numbers is significant. Ex. 2,806, 0.02806A zero at the end of a number and to the right of the decimal is significant. Ex: 0.0028060, 2,806.0A zero at the end of a number and to the left of the decimal point is not significant if the value was not counted. Ex: 28,060 (normally would write in scientific notation to be clear about 4 sig figs)Example Problems 1.16 a-b, PP 1.16 a-b pg. 38Sig Fig Rules in Calculations Multiplication and Division The product or quotient must have the same number of significant figures as the least precise number in the problem. Example Problem 1.17 a-d pg. 38PP 1.17 a-dAddition and Subtraction The sum or difference can only be as precise as the least precise number used in the calculation. Round to the first uncertain digit. Example Problem 1.18 a-d pg. 39PP 1.18 a-dMultistep Problems Keep track of sig figs throughout the stepsEx 1.19 a-d pg. 40PP 1.19 a-dRounding Numbers Example 1.20 a-e Assessment: Microscope Lab, Lipstick Lab, Sig Fig Practice Calculations, Exam Unit 3: Crime Scene Analysis and Physical Evidence Preserving and Recording the Crime Scene Secure and Isolate the Crime Scene First officer must preserve and protect the area. (This occurs only if no medical assistance is needed or arrest needs to be made.)Officer protecting it must have the authority to exclude everyone. (People entering can damage evidence.)Boundaries of the scene are established, perp’s entry and exit are identified, evidence is marked and photographed, and then a walk-through is completed. Witnesses are identified an separated. (Questions asked on pg. 25 Orange book)Record the Scene Photography Objects must not be moved until they have been photographed from all necessary angles. (Only exception is if injured people needed treatment.) **If moved before photography, notes should be taken in the report. Digital cameras are used with a megapixel of 12+ for high resolution images. Procedures Area in which the crime took place and all adjacent areas where important acts occurred should be photographed. Overview photographs of the entire scene and surrounding area, including points of exit and entry, must be taken from multiple angles. If indoors, the entire room should be photographed to show each wall area as well as rooms adjacent. Photographs must be taken to show the body’s position and location relative to the scene. Once removed, the area underneath the body should be photographed as well. All physical evidence should be photographed to show their position and location relative to the scene. Clos-ups should be taken to record details as well as a photograph with a ruler to show scale. Four photograph types are required at minimum for each piece of evidence. OverviewMedium-Range Close-upClose-up with scale All photographs typically contain labels including date, time, location, direction facing, evidence number (if evidence), and name of photographer. Sketches Rough Sketches contain:Accurate depiction of the dimensions of the scene showing the locations of all objects having a bearing on the case. Objects are located in the sketch by distance measurements from two fixed points and must be accurate. Each object is assigned a letter. If outdoors, you will need a datum point which is a fixed point of reference. All evidence collected must also be measured from the datum point. Always indicate north on the sketch. Include a legend on the sketch including the following:Legend showing letters that correlated to object. Case numberLocationDate and time of dayType of crimeVictim and name of sketch artist. Finished Sketches Typically more professional in appearance and is usually done via a CAD program. More detailed and specialized final product. Notes Must include a detailed description of the scene with the location of items of physical evidence recovered. Must also ID time an item was discovered, by whom, how and by whom it was packaged and marked, and the disposition of the item after it was collected. Many choose to tape record and transcribe it at a later time. Dealing with Physical Evidence Conduct a Systematic Search for Evidence Even when evidence and suspects are apparent, a search must be completed. Failure to do so, can lead to accusations of negligence or charges of a cover-up. Search patterns depend on the size and locale of the scene and number of people in the search. Strip or line search Grid search Spiral search Wheel/Ray search (good for missing persons)Quadrant or zone search Collecting and Packaging Physical Evidence Collection Practices Clothing items should be handled carefully and wrapped separately to avoid loss of trace materials. Critical areas of the crime scene are vacuumed and sent to the lab for analysis. Fingernail scrapings should be taken. (when deemed necessary)Tissues and organs are examined in deceased individuals for pathological and toxicological evidence. Handling Evidence Must handle and process evidence in a way that prevents any change from taking place. (Any change makes evidence unusable.) Collect evidence intact, which means not removing blood, hairs, fibers, soils, or other trace evidence. (Common sense used here.)Packaging Evidence Forceps, gloves, and disposable or sanitized equipment is used for collection. ALL EVIDENCE PACKAGED SEPARATELY. Types of collection containers vary:Plastic pill bottles are used for hairs, glass, fibers, and other small types of evidence. Manila envelopes, paper bindles (show how to make in class), screw gap glass vials, sealable plastic bags, or metal pillboxes are also good options. (ordinary envelopes are not used)Charred debris must in airtight containers to prevent evaporation of volatile residue using paint cans or sealed jars. Biological materials should only be collected using disposable tools and are typically placed in paper bags after drying to allow circulation and prevention of mold growth. Biohazard stickers are used in this case. (Pg. 63 black book)DNA evidence is easily contaminated and must be handled with extreme care. Face masks are worn when collecting this type of evidence. Same protocol as biological materials. Maintaining Chain of Custody All items should be carefully packaged and marked upon their retrieval. Collector’s initials and date of collection with case number and evidence number. Chain of custody must be established when evidence is presented in court. Every person who handled or examined evidence must be accounted for. (If not, it ruins integrity of evidence.)Shows the collector’s initials, location of evidence, and date of collection for each transfer. Obtaining Standard/Reference Samples Reference samples are known samples that allow for comparisons during the analyzation of evidence. Ex: Hit and Run suspects may be asked for a sample of paint from their car to compare to the crime scene evidence. Other examples would be taking hair from both victims and suspects, buccal swabs, or substrate controls. (collecting a surface believed to be exposed to an accelerant vs not exposed in an arson case)Submitting Evidence to the LabMost labs require an evidence submission form accompany all evidence. Must provide a brief history of case. Kind of examination requested Case details such as Crime and CountyVictim and SuspectSubmitting agencyInvestigator name. Crime and Accident Reconstruction Process of reproducing the actions and circumstances of an accident or crime based on examination and interpretation of evidence. Relies on evidence to help establish a timeline of events and relationships between evidence and victims/suspects. Crime Scene Staging Intentional altering of a crime scene in order to disguise what really happened. (Must be aware when performing a reconstruction)Murder appear as a suicide, a murder appear as a burglary, homicide as an accident, etc. Accident Investigation Steps Reporting (pg. 375 blue book…print for kids)At-The-Scene Investigation Photographs (same as crime scene)Measurements (same as crime scene)Coefficient of FrictionMeasures the roughness of a surface. Skid marks are an important piece of evidence when calculating what occurred in an accident. **Mass and temp are negligible. S2 = 255dfS = speed (km/h)D = distance (m)F = coefficient of friction (based on surface of the road)255 is a constant in order to adjust units. This equation can be used to estimate a range of speed using the coefficient of friction ranges. (pg. 377 blue book) Example pg. 377 blue bookTechnical Follow-upThis step (and the steps following) only occurs when a crime is committed. Paint samples taken, forensic pathologists complete and file autopsy reports including toxicology. Accident Reconstruction Rely on the following Laws of Physics Law of Conservation of Energy All energy is conserved. One car will do work on another car in an accident. Work is the transfer of energy measured by taking the force x distance. Laws of Motion First Law: Inertia Second Law: F = m x a Third Law: Every action, there is an equal and opposite reaction. Law of Conservation of Momentum Momentum of a system remains unchanged unless a force acts on it. Momentum (p) = mass x velocity. Cause Analysis (Final step)Attempt to determine the indirect cause or conditions that resulted in the accident. Most accidents are caused by three categories of factors:Environmental Conditions Human error Vehicle equipment malfunctionPitfalls of ReconstructionPossible flaws in logic that might lead to poor reconstruction include:Fallacies of logic Deliberate deception FraudHaste InexperiencePressure Unevaluated surmisePhysical Evidence Lifeblood of a criminal investigation. Common types include: biological fluids, documents, drugs, explosives, fibers, fingerprints, firearms, glass, hair, impressions, organs, paint, plastics, powder residues, serial numbers, soil, tool marks, vehicle lights, and wood / vegetative matter. Examination of Physical Evidence Identification Identify the physical or chemical identify of a substance with as near absolute certainty. Adopt specific testing procedures. (accepted)Number and type of tests needed to ID a substance must be sufficient enough to exclude all other substances. Comparison As we have stated before most specimens must be compared with a standard or reference specimen in observations and tests to determine if they have a common origin. Types of Characteristics in Evidence Individual Characteristics Evidence that can be associated with a common source with an extremely high degree of probability. Examples: ridge characteristics of fingerprints, comparison of random striations on bullets or tool marks, comparison of irregular and random wear patterns in tires and footwear, comparison of handwriting characteristics, fitting together of irregular edges of broken objects. Class Characteristics Can be associated only with a group and never a single source. Examples: paint chips from a car (if 1-2 layers thick), blood typesBlood and Product Rules Uses a series of blood factors to increase the probability. Example: Bloodstain in the O.J. Simpson case has the following factors:Type A (26%)EsD (85%)PGM 2+2- (2%) The product rule calculates the product of these three factors to calculate the frequency of the population that would have this combination. 0.26 x 0.85 x 0.02 = 0.0044 or 0.44% of the population. (1 in 200) Forensic Databases Integrated Automated Fingerprint Identification System (IAFIS)Combined DNA Index System (CODIS)DNA from arrestees can be obtained under probable cause. Rapid DNA could become a technique in the future as part of a booking procedure where a DNA profile could be created and uploaded to CODIS in as little as 90 minutes. National Integrated Ballistics Information Network (NIBIN)Only produces a short list of candidates to manually compare. International Forensic Automotive Paint Data Query (PDQ)Contains chemical and color information pertaining to original automotive paints. Assessments: Reconstruction Activity, Crime Scene Mapping Lab, Evidence classifications.Unit 4: Death Investigations and Anthropology Topic 1: Physical Trauma Described as any serious or life threatening physical injury, wound, or shock. Blunt forced or sharp force trauma. CSI, forensic nurses, MEs, or coroners process this evidence. Evidence Force applied to the body (F = m x a) Weapon’s surface area and mass (P = force / SA) Large SA inflicts less of a severe injury (flat board vs metal rod)Part of the body affected Types of Trauma Blunt Force Trauma (caused when victim is hit by something hard, but doesn’t break skin) *Includes offensive and defensive woundsAbrasions (results when the body rubs against a rough surface and a part of the epidermis is removed)Reddish brown color when alive, yellow after death. Brush, impact (bony areas), and patterned abrasions. Contusions (a bruise due to broken blood vessels below the surface of the skin)Hematoma (swelling due to bleeding)Shock can occur if extensive bruising occurs and oxygen is lost. Lacerations (tear in the tissue due to a sliding or crushing force)Linear or Y-shapedSharp Force Trauma (weapons such as knives, glass, etc.)Stab wounds (any wound caused by a knife)Hesitation marks (wounds indicating self infliction)Penetration wounds (punctured organ)Perforating wounds (puncture an organ and come out other side)Hilt abrasion (if knife goes straight into the body, hilt is aligned with knife, but if at a downward angle the hilt will be above the stab wound)Wound pattern indicates weapon used (knife, ice pick, etc.)Incised wounds (cuts produced by sharp edged objects but is longer than it is deep)Don’t offer clues about the weapon, not fatal (except in suicide cases)Found on victim hands as defensive wounds. Chop wounds Cause deep wounds that cause deep internal injuries and bone fractures. Caused by axes, machetes, and meat cleavers. Therapeutic wounds (surgery cuts)Asphyxia Interference with the intake of oxygen. Carbon monoxide in a fire scene. (if high, victim was breathing at time of fire, same with soot)Petechiae are very small pockets of blood in tissues of eyelids due to capillaries bursting. (Common in death from hanging) Break in hyoid bone indicates strangulation. (Not commonly broken in hanging.)Smothering often passes materials into nose and throat. Gunshot Wounds Estimating range of fire is one of the most important characteristics to analyze. Wound track must be observed and documented. Topic 2: Manner, Mechanism, and Cause of Death Manner of Death: methods from which a person can dieNatural death (interruption and failure of body functions resulting from age/disease) **most commonAccidental death (Unplanned events)Suicidal death (Purposefully killing herself or himself)Homicidal death (death of one person intentionally caused by another)Beating, shooting, burning, drowning, strangulation, hanging, suffocation Undetermined Cases where ME cannot make the determinationHow would you categorize the manner of death?A man with a heart condition is assaulted and dies from a heart attack during the assault.An elderly woman dies due to neglect by her son, who lived with her. Cause of Death Reason someone dies. Includes:Disease, physical injuries, stroke, poisoning, or heart attack. Proximate cause of death: underlying cause of death (not final cause)Beating that causes death due to kidney failure caused via beating (Proximate cause is beating)Mechanism of Death Describes the specific change in the body that brought about the cessation of life. Examples of Mechanisms Loss of blood, cessation of brain function, cardiac arrest, trauma to the body. Cause and mechanism stated in a single statement on death certificates “John died from massive trauma to the body leading to respiratory arrest.”Trauma is the cause and the mechanism is respiratory arrest. Topic 3: Body Changes After Death Death can be defined as occurring when enough individual cells die that the heart or brain stops functioning. Sequence of events. 2 stages of death Stage 1: Stoppage The heart stops, so blood is no longer pumped, and oxygen and glucose delivery to cells is halted. Leads to cell death. Less energy for cells to live. Lower oxygen/glucose per cell = less time cell stays alive. Cellular respiration changes to anaerobic respiration causing less energy and a buildup of lactic acid. Toxic wastes accumulate, pH of cells decreases, and the cell’s membrane ruptures. Stage 2: Autolysis Damaged/injured cells trigger autolysis (cell demolition)Enzymes released inside the cell, breaking down the contents and rupture the cell membrane. Mortises of Death Algor Mortis Cooling of the body following death. Investigators will insert thermometers into the liver or rectum. Postmortem interval estimates are accurate if death occurred within the past 24 hours. Shock, congestive heart failure, significant loss of blood cause lower temperatures, and fevers/heat strokes increase temperatures. How fast does a corpse lose heat?One hour after death, the body cools at a rate of 0.78 degrees Celsius and after 12 hours the body cools about 0.39 degrees Celsius. Time of death (hrs) = 37 degrees C – current body temp / 0.78If they lose more than 9.6 degrees C then they have been dead longer than 12 hours. Time of death (hrs) = (27.64 degrees C – current body temp / 0.39) + 12Factors that affect heat loss Body surface areas relative to mass (thin bodies = faster loss)Body position (extended body = faster)Clothing (reduce heat loss)Retention of fluids (retains fluids = slow heat loss)Colder environment (faster in cooler environments)Windy areas (faster in windy areas)Submerged bodies (if water is colder than body heat loss is fast)Body will cool in still water 2x faster than in air, and 3x as fast in running water. Casper’s Law: amount of decomposition that would take one week in air would take two weeks in water and eight weeks if buried. 12-2 Algor Mortis Practice Lab Livor Mortis Deceased people lying flat on their stomach would show reddish coloration on the skin of the face, neck, chest, abdomen, and front of legs. High pressure areas such as shoulder, elbows, hip bones, wrists, and areas where body was constricted will lack coloration. Livor mortis: death color that results when blood cells and blood vessels decompose. Hemoglobin from blood causes the coloration known as lividity. First becomes noticeable about 2 hours after death and becomes permanent after 8 hours. If death occurs between 2-8 hours, coloration will disappear if skin is pressed. Variables that affect the rate of lividity Temperature (increases rate of lividity with increased temps)Anemia (blood loss may cause livor mortis to not occur)Livor mortis can determine body position Coloration occurs on portion of the body on the ground Dual lividity: coloration occurs in two different areas. Coloring on back and along stomach would indicate that the body was kept in pone position for at least two hours and then moved before lividty became permanent. Rigor Mortis Rigor mortis means death stiffness. Temporary and can aide in estimating PMI. Becomes apparent in humans within 2 hours after death. Progresses from smaller muscle groups to larger muscle groups. After 12 hours, the body is at the most rigid state, but gradually disappears after 36 to 48 hours. Due to cells breaking down. Amount of rigor allows death time to be determined No rigor = death under 2 hours or over 48 hours Very rigor = Dead 12 hours Rigor in only face, jaw, and neck = death just over 2 hours Some rigor throughout the body, but lacks in face, jaw, and neck = death about 15 hours agoWhy does it occur?Skeletal muscles unable to relax because they cannot get oxygen and calcium accumulates in the muscle tissue. Joints also become rigid. Bones need to be broken to transport bodies in some cases. Factors affecting rigor mortis Ambient temperature (accelerates rigor with higher temps)Person’s weight (thinner = faster rigor)Clothing (no clothing = faster rigor)Illness Physical activity before death (sleep = slower rigor)Exposure to heat, cold, sun, and wind12-1 Lab on Rigor Mortis Topic 4: Autopsy and Decomposition Conducted when someone dies as a result of a crime or under unusual conditions. All states require autopsies for deaths due to violent crime, suicide, accident death within 24 hours of entering a hospital or having surgery, natural death when doctor is not present, death in police custody or correctional facility, or public health threat related death. Autopsy is defined as a medical examination to determine the cause and manner of death. Two typesClinical: Done for medical research study purposes when foul play is not considered. Also can be requested by family if a healthy person dies unexpectedly Forensic: performed when foul play is suspectedTwo parts: external and internal examination of the body. Forensic aspects (what is analyzed)Toxicology, Histology, Neuropathy, and serology Type of weaponWound depthPath of the bullet Nature, number, and type of wounds Defensive or offensive Bullet recovery to compare to bullets test fired Determination of cause of deathExternal Examination ME dictates all pertinent information into a recorder. Body is received, body is photographed and X-rayed, and body is checked for trace evidence. Body is removed from sealed bag and body temperature is taken. Livor mortis and rigor mortis is observed. Clothes and position of clothes are noted and then removed. Body is examined for evidence of injury and trace evidence. Hands (if bagged) are swabbed for gunshot residue or tissue samples under fingernails. Blood for DNA, semen, hair, tissue, fingernails, bitemarks Alternative light source is used to examine body (UV lights)Wounds examined before body is cleaned and prepared. Wound measurements are taken. Body is weighed measured, and sex, ethnic background, hair length, and color, eye color, and age are recorded. Tattoos, body piercings, or other marks are noted, documented, and photographed. Fingerprints are taken. Internal Examination Y-shaped incision made from shoulder to shoulder meeting at the breastbone and extending to the pubic bone. Ribcage is cut. Internal organs are removed, arteries and veins are cut, as are the larynx and esophagus. Stomach contents are removed. Cut from ear to ear across the forehead exposes the skull, which is opened. Brain is removed. Tissue samples are taken from organs to check for poisoning. All organs are examined for unusual appearance and trauma. Body fluids (urine, blood, saliva, ocular fluid, and vaginal swabs) are takenBody is prepared for a funeral home after reports are completed. Takes up to 6 hours. Stomach and Intestinal Contents It takes 2-6 hours for the stomach to empty its contents into the small intestine and 12 hours for food to leave the small intestine, and 24 hours for a meal to leave the body. Estimation of macromolecules in last meal Carbs, Lipids, Proteins, Nucleic acids Sudan = Fats Biuret’s = proteins Benedict’s = glucose Iodine = starch Able to estimate:Death occurred 2-6 hours after the last meal if stomach contents are undigested. If food is found in the small intestine, but not the stomach death occurred 6-12 hours after last meal. If food is found only in large intestine, death occurred 12 or more hours after a meal. Factors affecting digestion Amount Type Temperature Illness Stress *Murder Meal Lab Postmortem changes in the eye Surface of eye dries outCloudy film observed within 2-3 hours if eyes were open at death or 24 hours if eyes were closed. Potassium accumulates inside the eye after death and can be used to estimate PMI. Stages of Decomposition Time durations will vary due to environmental and physiological factors 5 stages Stage 1: Fresh Cell autolysis begins, muscles lose tone, bladder and rectum empty, onset of algor, livor, and rigor mortis, cloudy film forms over eyes, and flies arrive to deposit eggs. Body temp drops. Stage 2: Bloating / Putrefaction Blistering of the skin and internal organs causes skin slippage. (skin falls away from underlying tissue. Can place skin over someone elses’s finger to obtain fingerprints. Putrefaction (destruction of soft tissue due to bacterial activity occurs)Gas seepage and changes in body color. Abdominal swelling occurs (CO2)Internal pressure from fluids and foul smelling decomposition gases force fluids from body. Skin discoloration occurs, proteins break down, sulfurous odors are released. Loss or rigor / increased insect activity Stage 3: Active decay 7-23 days Bloating continues released hydrogen sulfide, methane, sulfur dioxide, putrescine, and cadaverine. Discoloration makes ID of skin color impossible. Ruptures in the skin occur leading to increased bacterial and insect activity. Soft tissues of body start to liquefy. Stage 4: Advanced Decay 3 weeks to 2 monthsGreatest loss of mass occurs due to insect infestation, action of bacteria, and purging of fluids. Fats decompose forming adipocere (greasy wax) Can preserve tissue. Stage 5: Dry or skeletal After 2 months Soft issues are gone, bones remain, and odors are gone. Factors affecting decomposition Age (young decompose faster)Size of body (larger = faster)Nature of deathClothes (slow down decomposition rate)Environment (70-99 degrees is fastest)Moisture (moist = fast)Exposure (air = fastest)Rule of Thumb PMI estimate Body feels warm and is limp (dead less than 3 hours)Body feels warm and stiff (3-8 hours)Body feels cold and stiff (8-36 hours)Body feels cold and limp (More than 36 hours)Autopsy Report Heading (name, age, and gender of the victim, case number, date and time of death, date, time, and location of exam, and names of personnel present at exam. External examination (Includes overall description of deceased such as build, height, and weight, ME notes diseases, disorders, or malformations, describes clothing, etc.)Evidence of Injury (describe evidence of all injuries, include movement of weapon, ID entrance and exit wounds and measure, records organ/tissue that came in contact with weapon)Internal examination (describe and weigh each major organ and notes abnormalities, describes microscopic findings, toxicology screenings, and records analysis methods.)Medical Examiner’s findings and opinions (summarizes findings and states his or her opinion on the cause and manner of death)Topic 5: Forensic Entomology Study of insects and their relation to a criminal investigation. Most commonly used to estimate time of death. After decomposition takes place, insects that feed on dead tissue are the first to infest the body within 24 hours. Most common insect is blowfly (green or blue in color)Lay eggs in remains which hatch to maggots. (2,000)Lifecycle of the blowfly can be used to help estimate PMI. Figure 11-8 on pg. 355 in Orange book (Print) Beetle succession on a decomposing body on pg. 359 in orange book (Print) **Most factors that alter time of death estimates also impact insect lifecycles. Topic 6: Forensic Anthropology and Odontology Use of skeletal anatomy to ID remains. Observe shape, structure, condition, and measurements of remains. Document estimated age, sex, stature, and ancestry along with trauma. Anatomy of Bones Contain calcium and phosphate and living bone cells. Bone maintenance performed by hormones and mineral levels. Bone marrow produces blood cells. Development and Number of Bones 206 bones in adults, babies have up to 300. Bones ossify from cartilage to bone over development at the growth plate. Older bones = narrower growth plate. Bones begin to break down after 30 years. Bones and Biological Profiles Bones and Geography Test for carbon (food) and strontium (groundwater) isotopes to determine where and how long a person lived in a certain area. Males vs Females Male skeletons are thicker and more robust. Skull (Table 4-1 on pg. 125 black book)Males: squarer mandible and eye shape Females: Rounded Males: rougher, frontal bone is low and slopes Females: smoother and rounded frontal bone. Pelvis Males: Narrower, heart shaped, sacrum is longer and curved inward. Females: Wider, oval shaped, sacrum is short and curves outwardEstimating Age (Table 4-2 on pg. 127)Determining age varies depending on the growth stage. Most infants and toddlers can be estimated using length of long bones or degree of fusion in skull and other bones. After the age of 21, age is estimated by the level of change the surface of the bones have undergone. See Table 4-2 for a summary of age determination for bones. Teeth /Odontology Baby teeth begin to fall out around 5-6 years old, first molars come in around 7, second molars around 12, wisdom teeth come in after 17 or not at all. After the age of 25, age and identification are difficult to estimate and relies on wear and tear patterns of teeth. Dental records Human Bite Marks (Ted Bundy) Bruising and swelling indicates person was bit while alive. Skull Sutures Coronal sutures close at 50, sagittal suture closes at 32, lamboidal suture closes by 30, and the squamosal suture closes after 60. Ancestry (Table 4-3 on pg. 128 black book)Indicated by the following:Shape of eye sockets Shape of nasal cavity Nasal index (ratio of width / height of opening x 100)Prognathism (projection of upper jaw) Estimating Height (Table 4-4 on pg. 128 black book)Measurements of the humerus and femurs can help estimate height. Calculations vary by sex and ancestries. *Print off calculations. Example: A femur measuring 49 cm belongs to an African American male. What is the height?2.10 x 49 + 72.22 (+/- 3.91 cm)Height = 171.21 to 179.03 cmForensic Anthropologist must answer:Skeletal Trauma causeIs a fragment a bone? (texture, color, interior)Human or animal?Which bone is it?Does the gravesite contain remains from one person or more?How long have the remains been buried?Were the markings on the bones made antemortem or postmortem?Assessments: Cause of Death, Estimating TOD, Bite Mark Lab, Anthropology Labs, Autopsy Lab (if time allows)Unit 5: Drugs and Toxicology Drugs are defined as natural or synthetic substances that are used to produce physiological or psychological effects in humans. Use accelerated during the 1960s. Modern uses include: necessary for sustaining and prolonging life, provide escapes from the pressures of life, or they are a means of ending life. 75% of evidence evaluated in crime labs is drug related. Drug Dependence Early laws focused on drugs that had “habit-forming” properties. Focused on opium, cocaine, and later marijuana. Dependence depends onNature of the drug Route of administration Dose Frequency of use Individual’s metabolism Personal characteristics of the userExpectations of the drug experience Society’s attitudes and possible response Setting in which the drug is used Types of Dependence Psychological Dependence Most users present normal appearances and remain both socially and economically integrated in the life of the community. *Not all are hopeless addicts. Develops from the individual’s desire to create a sense of well-being and to escape reality. No precise way to measure or predict the impact of drug abuse on the individual as it depends on the drug and the person. Alcohol, heroin, amphetamines, barbiturates, and cocaine results in high degree of involvement. Marijuana and codeine have a lower potential for psychological dependence. Physical Dependence Desire to avoid withdrawal sickness or abstinence syndrome leads to physical dependence. Body chills, vomiting, stomach cramps, convulsions, insomnia, pain, and hallucinations. Marijuana, LSD, and cocaine are drugs that cause anxiety when discontinued, but do not show abstinence syndrome. Develops when the drug user adheres to a regular schedule of drug intake. Interval between doses is so small that drug effects never wear off. Drug Psychological Dependence Physical Dependence Morphine High YesHeroin HighYesMethadone HighYesCodeine LowYesAlcohol HighYesValium ModerateYesAmphetamines HighUnknownCocaine HighNoCaffeine LowNoNicotine HighYesMarijuana LowNoLSDLowNoPCPHighNo Societal Aspects of Drug Use Most important element is how interwoven the drug has become in the fabric of the user’s life. More frequently the drug satisfies the person’s need, the greater the likelihood that they will become preoccupied with its use. Society must weigh the beneficial aspects of the drug against the harm of its abuse. (Alcohol discussion)Types of Drugs Narcotic Drugs Narcotic means numbness and deadening. Relieve pain and produce sleepWas used to classify any drug that is socially unacceptable – incorrect. Classes of Narcotic Drugs Natural Opiates (Derived from Poppy plant)Behave pharmacologically like morphine. Analgesics: relieve pain by suppressing CNS. Most commonly used opiate is heroin reacting morphine with acetic anhydride or acetyl chloride)Dissolves well in water and makes street preparation simple and delivery via injection is instant and with maximum sensitivity. High is 3-4 hoursCodeine Found in opium but is prepared synthetically from morphine. 1/6th as strong as morphine and is used as a cough depressant. Synthetic Opiates Methadone is the most common synthetic opiate. A person who received periodic doses of methadone would not get high if he or she then took heroin or morphine. Eliminates the addict’s desire for heroin with minimal side effects. = treatment centers = overabundance of drug = more leaked to drug market Oxycodone Used primarily to treat chronic pain. Used with a time-release formulation in the hopes it would reduce risk of abuse and addition (Didn’t go that way)Hallucinogens Drugs that can cause marked alterations in normal thought processes, perceptions, and moods. Types Marijuana Most widely used illicit drug in the United States. Derived from Cannabis plant, Cannabis sativa Consist of crushed leaves mixed with flower, stem, and seed. Plant also secretes a sticky resin called hashish. Contains the chemical tetrahydrocannabinol or THC. Produces psychoactive effects. Greatest concentration found in the resin, followed by the flowers and leaves, and little in the stem, roots, or seeds. Potency depends on mixture and is consumed by smoking or consuming. Medical Uses Reduction of excessive eye pressure in glaucoma Lessening of nausea caused by anticancer drugs. Muscle relaxant. Extended Use Can lead to increased heart rate dry mouth, reddened eyes, impaired motor skills and concentration, decreased sperm counts, and frequent hunger. Other Hallucinogens Natural Substances Mescaline and Psilocybin Synthetic LSD (Lysergic diethylamide)Derived from a fungus that attacks grasses and grains. Appears as a pill, added to a sugar cube, or absorbed on paper. Effects first discovered when chemist Albert Hofmann accidentally ingested some in his lab. Symptoms include mood swings, anxiety, tension. Very potent = 25 micrograms can lead to vivid hallucinations that can last up to 12 hours. Can lead to flashbacks and psychotic reactions after use. PCP (phencyclidine)Simple chemical process leads to labs in garages or bathrooms using cookbook methods with little knowledge of chemistry. Often mixed with other drugs like LSD and amphetamines and is sold as a powder called “angel dust”, a pill, or as a liquid. 1-6 milligram dosage leads to feelings of strength, invulnerability, dreamy sense of detachment, and soon becomes unresponsive, confused, and agitated Can lead to depression, irritability, feelings of isolation, audio and visual hallucinations, and paranoia. Depressants Drugs that slow down or depress the central nervous system. Types of Depressants Alcohol Most widely used and abused drug. Behavioral patterns of alcohol intoxication varies and depends on social settings, amount consumed, and personal expectation of the individual. Blocks brain’s control of thought processes and muscle coordination. Low doses inhibit mental processes of judgement, memory, and concentration. Personality becomes expansive and exudes confidence. Moderate doses reduces coordination, inhibits orderly thought processes and speech patterns, and slows reaction times. Higher doses can lead to individuals being highly irritable and emotional, unconsciousness, or can lead to a coma causing fatal depression of circulatory and respiratory functions. Barbiturates Derivatives of barbituric acid that are referred to as “downers” because they cause relaxation and a feeling of well-being, as well as sleep. Suppress vital functions of the CNS. Medical uses: phenobarbitalTaken orally (10-70 mg dose) and enters bloodstream in the small intestine. Illicit drug: QuaaludesAntipsychotics and Antianxiety Drugs Different from other depressants in the fact that they produce relaxing tranquility without impairing high-thinking faculties or inducing sleep. Includes valium, chlorpromazineHuffing Sniffing materials containing volatile solvents. All substances depress the CNS. Cause exhilaration, euphoria, slurred speech, impaired judgement, and double vision. Also may cause drowsiness, stupor, as well as liver, heart, or brain damage. Stimulants Range of drugs that stimulate the CNS. Types of Stimulants Amphetamines Share similar chemical structure and are commonly referred to as speed. Taken orally or intravenously. Symptoms include feeling of well-being, increased alertness, followed by decrease in fatigue and a loss of appetite. Also cause restlessness, instability, apprehension, and depression. Most commonly used is meth for its production of a more intense amphetamine experience. “speed binge” 500-1,000 mg every 2-3 hours. Can smoke it via “ice”. Done by evaporating meth solution. Lasts longer. Cocaine Developed by European psychologist Sigmund Freud. Extracted from a plant grown in the Andes of South America. Commonly sniffed or snorted and absorbed via mucous membranes. Stimulates pleasure center of the brain to a far greater degree than it would ever normally be stimulated. Most deaths are due to cardiac arrest or seizures. Crack is produced by mixing cocaine with baking soda and water and then heating the solution. Solution is dried and broken in tiny chunks. Delivers high in less than 15 seconds. Dark side of crack is that levels drop so quickly that the user feels depressed and desire to return to euphoria is so intense that habits are developed quickly. Peruvian farmers are paid $200 for coca leaves to make 1 pound of cocaine and refined cocaine is worth up to 20,000 dollars in the United States. Club Drugs Refers to synthetic drugs that are often used at nightclubs, bars, and raves. Includes MDMA (Ecstasy)GHB Roofies (Rohypnol) Ketamine Methamphetamine Symptoms vary GHB and Roofies depress the CNS and are often connected to drug-facilitated sexual assaults, rapes, and robberies. Cause dizziness, sedation, muscle relaxation, headaches, and nausea. Also can cause euphoria, relaxation, and increased sex drive. Anabolic Steroids Synthetic compounds that are chemically related to the male sex hormone testosterone. Promotes development of secondary male characteristics Accelerates muscle growth Symptoms Little or marginal evidence of enhanced strength or athletic performance. Liver cancer and other liver related issuesInfertility Diminished sex drive Male characteristics in femalesMood swings and unprovoked acts of angerDepression Drug Control Laws Severity of a drug related penalty depends on the weight of the drug or the concentration of a drug in the mixture. Chemist must provide a report that contains all information needed to properly charge a suspect. Controlled Substances Act Federal law establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s potential for abuse, potential for physical and psychological dependence, and medical value. Schedule I: High potential for abuse, no accepted medical use in the United States, and/or lack accepted safety for use in treatment. Includes heroin, marijuana, and LSD. Schedule II: High potential for abuse, currently accepted medical use with severe restrictions, and a potential for severe psychological or physical dependence. Include opium and its derivatives, cocaine, methadone, PCP, amphetamines and barbiturates. Schedule III: Less potential for abuse, currently accepted medical use in the United States, and a potential for low or moderate physical or high psychological dependence. Includes codeine drugs and anabolic steroids. Schedule IV: Low potential for abuse and have current medical use in the United States. Limited dependence. Includes tranquilizers, valium. Schedule V: Show low abuse potential, have medical use in the United States, and less potential for producing dependence. Includes Robitussin. Unscheduled drugs include alcohol, tobacco, caffeine, aspirin. Criminal Penalties under the Act Most severe penalties are associated with drugs listed in schedules I and II. Drugs included in schedules I and II, first offense is punishable by up to 20 years in prison and a fine up to a million dollars.Stipulates that an offense involving a controlled substance analog ( chemical substance very similar in chemical structure to a controlled substance or aka designer drugs) are treated as controlled substance drugs. Also regulates the manufacture and distribution of precursors or chemical compounds used by labs to synthesize abused drugs. Forensic Drug Analysis Screening and Confirmation Select analytical procedures that will ensure specific identification of a drug. Plan of action is split into two phases:Screening Tests Tests to reduce the possibilities to a small and manageable number. Done by subjecting the material to a series of color tests that produce characteristic colors for the more commonly encountered illicit drugs. Pinpointing and confirming the drug’s identity Confirmation tests are chosen and ran by the chemist to ID drug. Each individual test is insufficient, but a group of tests that share the same identify becomes sufficient. Qualitative and quantitative determination. Tests used include: color tests, microcrystalline tests, chromatograph spectrophotometry, and mass spectrometry. Color Tests Useful for screening purposes only and are never taken as conclusive identification of unknown drugs. Used in fieldFive primary color test reagents Marquis: Turns purple in the presence of heroin and morphine, as well as other opium derivatives. Turns orange/brown when mixed with amphetamines and meth. Dillie-Koppanyi: Turns violet-blue in presence of barbiturates. Duquenois-Levine: Turns purple when chloroform is added to test for marijuana. Van Urk: Reagent turns blue-purple in the presence of LSD. Scott Test: Used to test for cocaine and will turn a solution blueMicrocrystalline Tests Drop of a chemical reagent is added to a small quantity of the drug on a microscope slide. A reaction occurs producing a crystal precipitate. The size and shape of the crystals are characteristic of a drug. Chromatography Separating and tentatively identifying the components of a mixture. Helps ID ingredients in drugs. Based on the fact that chemical substances escape to surrounding environment when dissolved in a liquid or absorbed by a solid surface. 2 main methods Thin-Layer Chromatography Rapid and sensitive. Cost effective for forensic labs. Uses a solid stationary phase and a moving liquid phase to separate components of a mixture. Individual components will appear as a series of dark or colored spots as they separate out, which is compared to a known sample for identification. Cannot provide absolute identification and must be used with other testing procedures. A glass plate or paper serves as a stationary phase while the liquid serves as the moving phase. Drug can be dissolved in a solvent. If substance is colorless, plate will be viewed with UV light or sprayed with a chemical indicator. Lipstick LabGas Chromatography Separates mixture based on distribution between a stationary liquid phase and a moving gas phase. Sample is placed in a column and a carrier gas is moved through the column. Those components with a greater affinity for the moving gas move through the column more quickly. Measured and identified via retention times. Requires further testing as well. Spectrophotometry Identify a substance by exposing it to a specific type of electromagnetic radiation. Can specifically identify a material unlike chromatography. Follows Beer’s Law Substances absorb a selective amount of radiation and reflect the rest. Produces a graph called a absorption spectrum. Methods UV and Visible Spectrophotometry Does not provide a definitive result, but can narrow down the potential list of drugs. Infrared Spectrophotometry Provides a more complex pattern and has enough characteristics to identify a substance specifically. Provides the “fingerprint” of that substance. Specific form of evidence. Mass Spectrometry Method that can be used in conjunction with gas chromatograph to identify a substance. First must be separated using gas chromatography and passed through a mass spectrometer. A beam of high energy electrons are aimed at the sample’s molecules. This causes the molecule to lose electrons and to acquire a positive charge. The positive ions decompose and pass through an electric or magnetic field and are separated due to masses. This pattern produces a “fingerprint” to the substance. Most widely used lab technique and can be hooked up with computer programs to provide a database of spectrums for different substances allowing quick identification. Introduction to Toxicology Study of drugs, poisons, toxins, and other substances that can harm a person. Identify method of exposure: Intentional, accidental, or deliberate. Toxicity (degree to which a substance is harmful to a given person at a given time.)Depends on dose, duration, nature of exposure, interactions, or by-products formed when broken down. Role of Forensic Toxicology Detect and identify drugs and poisons in body fluids, tissues, and organs. Work in crime labs and hospitals. Limited to matters that pertain to violations of criminal law. Alcohol is the most prevalent drug in their role. Toxicology of Alcohol Metabolism of Alcohol 3 basic steps of metabolism of alcohol Absorption Alcohol slowly enters the body’s bloodstream and is carried to all parts of the body within minutes. Factors that determine rate of absorption: total time taken to consume the drink, alcohol content, amount consumed, and quantity and type of food present in the stomach. Examples: Beer is absorbed more slowly than alcohol, alcohol consumed on an empty stomach absorbs faster. Longer the total time required for complete absorption = lower the peak alcohol concentration in the blood. Max BAC may not be reached until 2-3 hours have elapsed. 20% of alcohol is absorbed through the stomach walls into the blood system while the remaining alcohol is absorbed via the small intestine. Eventually it makes its way to the liver and then is carried in the blood throughout the body and to the heart. Once in the heart, the blood is circulated to the lungs (alveoli) to be aerated. Oxygen moves into the blood and carbon dioxide / alcohol leaves via the breath you exhale. The remaining alcohol is sent back to the heart via the blood and distributed via the body in arteries. Distribution Alcohol becomes distributed uniformly throughout the watery portions of the body. Alcohol concentration is 41% higher in the arteries compared to the veins prior to distribution and absorption being completed. Benefits the subject if they are tested as blood samples are taken via the veins. Elimination Eliminated via oxidation and excretion. 95-98% of alcohol is oxidized to carbon dioxide and water. Oxidation takes place in the liver and alcohol dehydrogenase converts alcohol to acetic acid which is then converted to CO2 and water. Excretion is the process where the remaining 2-5% of alcohol leaves the body unchanged via breath, urine, or perspiration. The breath reflects the concentration of alcohol the best hence the breathalyzer testing. Elimination varies in different individuals, but the average rate is 0.015% per hour. Blood Alcohol Concentration A true determination of the quantity of alcohol impairing a person’s normal body functions would be done by removing a portion of brain tissue….obviously we can’t do that if they are alive. Blood is the best substitute as it is the substance that transports alcohol throughout the body. CSF or vitreous humor can also be analyzed post-mortem for alcohol content. Determined via Widmark Formula (Does NOT take into account food!) Graph on pg. 264 is an example of estimating using food. Male Formula[(A) x (D) x (5.14)] / [(wt) x (0.73)]Female Formula [(A) x (D) x (5.14)] / [(wt) x (0.66)]Equation Basics A stands for alcohol consumed in ounces. Beer is typically 12 ounces, wine is 5 ounces, and hard liquor is 1.25 ounces.Normally mixed drinks are 8 oz servings containing 1.25 ounces of liquor. 80 proof = 40%, 100 proof = 50%D stands for % alcohol written as a decimal. Beer contains 6% alcohol, wine contains 12%, and hard liquor contains 40%. Wt stands for weight in pounds. When consumed over a long period of time additional calculations should be done:Estimate the hours since drinking commenced. Multiply the hours by 0.015 (elimination rate)Subtract the above value from your BAC calculation. Testing for Intoxication Breath Testing for Alcohol Breath test measures the alcohol concentration in the pulmonary artery by measuring its concentration in the breath. If absorption is complete the differences between blood and breath tests are minimal. Three tools used today (all based on alcohol standards)Breathalyzer (developed by a former captain of the Indiana State Police) used chemicals to test alcohol content. Light absorption devices (similar to what we discussed to ID components of drugs)Fuel cell detectors (see pg. 258)Procedure Accepts no less than 1.1 to 1.5 L of breath and must blow for a minimum time such as 6 seconds. Must avoid mouth alcohol which results from belching or vomiting or from gargling alcohol based mouthwash. Dissipates in 15-20 minutes, so waiting that length of time should give a more accurate result. Deep, sustained breath also gives a more true BAC reading than short, shallow breaths. Field Sobriety Testing Consist of a series of psychophysical tests and a breath test. Tests include:Horizontal-gaze nystagmus: involuntary jerking of the eye as it moves to the side. BAC levels of 0.10 tends to cause involuntary jerking of the eye at 45 degree angles. Walk and turn / One leg stand: divided attention tasks that test the subject’s ability to comprehend and execute two or more simple instructions at one time. Alcohol and the Law The first BAC level that indicated a person was under the influence was 0.15 percent, but has since been lowered to 0.08 percent. In 2000, the federal law was set that an individual meeting or exceeding 0.08 shall be deemed intoxicated for noncommercial drivers. Commercial truck and bus drivers are deemed intoxicated at 0.04 percent. Canada, Italy, Switzerland, and the UK share the same law. Finland, France, Germany, Ireland, Japan, the Netherlands, Australia, and Norway all have a 0.05% limit. Sweden has the lowest allowing only 0.02%. A person is 4x more likely to get into an accident at 0.08% and 25x more likely at 0.15%. Body weight plays a role as well (pg. 264)Implied consent lawStates that the operator of a motor vehicle on a public highway must either consent to a test for alcohol intoxication, if requested, or lose his or her license for a designated period which is normally 6 months to a year. Techniques used in toxicology Must device an analytical scheme to detect, isolate, and identify a toxic substance. Testing Procedures (in order)Acids and Bases Acids are 0-6 on pH scale and Bases are 8-14. Toxicologists can control drugs recovered by controlling pH. Used to extract drugs from bodily fluids. Detecting Drugs in Hair Drugs remain in bloodstream for about 24 hours, in urine for 72 hours. Hair can be used to determine use for longer than 72 hours. Drugs diffuse into the base of hair and can be tracked by its location in the hair shaft. Hair grows at 1 cm per month so it can be used to track a timeline for drug use. Assessment: Drug Analysis Lab, BAC Calculations Unit 6 Fingerprinting History of Fingerprinting Prior to fingerprinting, the first attempt at criminal identification was made by Alphonse Bertillon. Proposed anthropometry: system of precise body measurements accompanied with a portrait. (11 total) Assumed the skeletal structure did not change from age 20 on. Largest setback came in the William West case in 1903….suspect who was supposed to be William West based on measurements and portrait….William West was already in prison. (fingerprints would later set the two men apart)Early Use of Fingerprints China was the first to use fingerprints as a form of identification by having people sign documents using fingerprints. Scot Henry Fauld was the first to propose use of fingerprinting in criminal investigations, but was turned down. Francis Galton published the first textbook on fingerprints suggesting methods of using them and assigned the first three patterns used today: loops, arches, and whorls. Also, established that they do not change over time. Became integrated by 1924 (FBI)1999: United States v. Byron C. Mitchell : challenged the use of fingerprints as evidence. Led to the ruling thatHuman friction ridges are unique and permanentHuman friction ridge skin arrangements are unique and permanent. Fundamental Principles of Fingerprints First Principle: Fingerprints is an Individual Characteristic; no two fingers have yet been found to possess identical ridge characteristics. To date the FBI has 50 million fingerprint records and no identical images between two people. General shape or pattern does not determine the individuality Ridge characteristics determine individuality (150)Ridge ending Bifurcation Island ridge Dot Bridge Spur/HookEnclosure / EyeDouble Bifurcation Delta Trifurcation Point by Point Comparisons used to ID individuals in courtUp to expert to determine how many ridge characteristics two prints must share to determine identity (1973)Most fall in 8-16 range. Second Principle: A fingerprint remains unchanged during an individual’s lifetime. Fingerprints formation Reproduction of friction skin ridges to provide us with a firmer grasp and a resistance to slippage. (Ridges and grooves)Produced by dermal papillae during fetal development..and only enlarge throughout one’s life. (Layer between dermis and epidermis)Pores line our skin ridges secreting sweat and oils which leaves our pattern or fingerprint. Attempts at changing fingerprints Injuries can cause scarring if deep enough (1-2 mm), however it gives new characteristics. John Dillinger applied acid to his own fingerprints…however after his death, fingerprints show his efforts made no difference. Third Principle: Fingerprints have general ridge patterns that permit them to be systematically classified. Loops (65%) Must contain one or more ridges entering from one side of the print, recurving, and exiting the same side. Ulnar or radial loops. Ridge counts are taken by counting the number of ridges between the core (center of a loop) and the middle of the delta (triangular ridge pattern). Whorls (30%)4 types Plain whorls: have at least one ridge that makes a complete circuit. (24%) Contains two deltas. Central pocket whorls: similar to the plain whorl, but more circular. Contains two deltas. (2%)Double loop whorls: made up of two loops combined in one fingerprint and two deltas. (4$)Accidental: Two or more deltas and a combination of two of the other patterns. (0.01%)Arches (5%)Plain arches (4%): ridges entering one side, rising in the center, and exiting the other side. No delta existsTented arches (1%): similar to plain arch, but a sharper peak. Putting it all together ACE-V Process Analysis: examiner identifies distortions as well as surface or deposition factors that may impinge on the print’s appearance. **Declares if print is adequate. Comparison: Examiner compares prints at three levels. Level 1: General ridge flow and pattern configuration. Level 2: Details can individualize a print. Level 3: Examination and location of ridge pores, breaks, creases, scars, and other permanent characteristics. Evaluation: Requires one of three decisions to be made1: Identification 2: Exclusion 3: Inconclusive Verification: Requires an independent examination of the questioned and known prints and a conclusion must be reached between the two examiners. Classification of Fingerprints Primary classification system of the FBIPart of the original Henry system and divides all fingerprint cards into 1,024 groups. Process involves pairing up fingers as fractions R. Index / R. Thumb, R. Ring / R. Middle, L. Thumb / R. Little, L. Middle / L. Index, and L. Little / L. Ring. Relies on the presence or absence of the whorl pattern for primary classification and uses a number/fraction set. If a whorl pattern is found on any finger of the first pair = 16, on the second par = 8, third pair = 4, fourth pair = 2, and last pair = 1. Total the top and bottom of the fraction and 1 to the top and bottom. 25% of population is in the 1/1 category. Fraction value is a CLASS CHARACTERISTIC! Must be used with ridge patterns. AFIS Automated Fingerprint Identification System Focuses on ridge endings and bifurcations in addition to the position and orientation of other patterns to produce a geometric pattern. Only provides a list of similar prints based on criteria….up to examiner to compare the two prints. Methods of Detecting Fingerprints Types of Fingerprints Visible prints: made by fingers touching a surface after the ridges have been in contact with a colored material such as blood, paint, ink, or grease. Plastic prints: ridge impressions left on a soft material such as putty, wax, soap, or dust. Latent prints: Impressions caused by the transfer of body perspiration or oils present on finger ridges to the surface of an object. (Invisible)Methods for Detecting Fingerprints Detection of Prints (Latent)RUVIS detects prints by using UV light to reflect off the print. Preserved by lifting with tape or via digital imaging. Developing Latent Prints Fingerprint Powders Gray powders (aluminum) or Black powders (carbon)Fluorescent powders used as well Ninhydrin Chemical used to produce a purple-blue color with amino acids found in sweat. Takes between 1-24 hours. Used on paper products. Cyanoacrylate Vapor (Supeglue fuming)Used primarily on household items, plastic, metal, glass, and skin. Sample is placed in a fume or vapor tent with heated super glue so it vaporizes. Fumes react with amino acids and forms a white print. Silver Nitrate (Physical Developer)Used on wood, Styrofoam, or items that were previously wet. Dipped or sprayed in silver nitrate and reacts with chloride from salt in sweat to form a black or reddish brown print under UV light. Iodine Fuming Used primarily for paper surfaces. Similar to ninhydrin. Oldest method used. Produces a brownish print that fades very quickly…must be sprayed with starch to last few weeks. Combines with carbohydrates. Assessments: Fingerprint Lab, Fingerprint Analysis Unit 7 and 8: DNA Serology and DNA ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download