Chapter 2: Types of Evidence - Georgetown ISD



Chapter 2: Types of Evidence

“You can learn a lot by just watching.”—Yogi Berra, former New York Yankees catcher and sage

Types of Evidence

■ Testimonial—

■ Physical—

Reliability of Eyewitness

People are likely to view the same scene in different ways depending on their positions, line of sight, familiarity with the area, and other factors that can interfere with a person’s ability to remember details.

Interferences include:

■ Nature of the ______________and the situation in which the crime is observed

■ Characteristics of the witness (age, disability, etc.)

■ Manner in which the information is retrieved

■ Witness’s prior relationship with the ______________

■ Length of time between the offense and the identification

■ Any prior identification or failure to identify the ______________

■ Any prior identification of a person other than the defendant by the eyewitness

What do you remember? List here:

According to The Innocence Project (2008) "______________________________________________________

_______________________________________________________________________________________________." Still, the criminal justice system profoundly relies on eyewitness identification and testimony for investigating and prosecuting crimes.

A crime that is extremely traumatic for an eyewitness may affect his/her recall of the event. For example, a witness confronted with a weapon tends to focus on the weapon rather than the perpetrator’s face. Someone who is able to focus on a perpetrator's face for a minute or longer will tend to have a more accurate memory than someone who saw the person for only a few seconds.

Studies have shown that faces that are either highly attractive, highly unattractive, or distinctive are more likely to be accurately recognized. Simple disguises, such as hats or sunglasses, can interfere with accurate eyewitness identification. However, body piercings and tattoos increase the likelihood of an accurate identification.

The time of day in which the crime occurred as well as a person’s view of the scene may affect what a he/she is able to see. In addition, a person who is familiar with the area in which the crime took place, may have a better recall of the positions of the victims or suspects.

Crime Scene Challenge- Answer each question below.

1. _______________ 4. _______________ 7. _______________ 10. _______________

2. _______________ 5. _______________ 8. _______________

3. _______________ 6. _______________ 9. _______________

Eyewitness

A police _______________may be developed from the witness testimony by a computer program or forensic ________. As a result of the influences in _______________memory, physical evidence becomes critical.

Value of Physical Evidence

Generally more reliable than _______________

Can _______________that a crime has been committed

Can _______________or refute testimony

Can link a suspect with a victim or with a ____________

Can establish the ____________ of persons associated with a crime

Can allow reconstruction of _______________of a crime

Physical Evidence is used to answer questions about:

■

■ how the victim was killed

■

■ sequence of events

A forensic scientist will compare the questioned or unknown sample with a sample of known origin.

Physical Evidence

Indirect evidence:

Circumstantial evidence:

Class Evidence:

Probative value:

Types of Physical Evidence

■ Transient Evidence—temporary; easily changed or lost; usually observed by the first officer at the scene

■ Pattern Evidence—

■ Conditional Evidence—produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances or sequence within a particular event

■ Transfer Evidence—

■ Associative Evidence—items that may associate a victim or suspect with a scene or each other; ie, personal belongings

Examples of Transient Evidence

■ Odor—putrefaction, perfume, gasoline, urine, burning, explosives, cigarette or cigar smoke

■ Temperature—

■ Imprints and indentations—footprints, teeth marks in perishable foods, tire marks on certain surfaces

■ Markings

Examples of Pattern Evidence—most are in the form of imprints, _______________, striations, markings, _______________or deposits. Clothing or article distribution, Gun powder _______________, Material damage, Body position, Tool marks, ______________________________

Examples of Conditional Evidence

■ Light—headlight, lighting conditions

■ Smoke—

■ Fire—color and direction of the flames, speed of spread, temperature and condition of fire

■ Location—of injuries or wounds, of bloodstains, of the victim’s vehicle, of weapons or cartridge cases, of broken glass

■ Vehicles—

■ Body—position, types of wounds; rigor, livor and algor mortis

■ Scene—

Classification of Evidence by Nature

■ Biological—blood, semen, saliva, sweat, tears, hair, bone, tissues, urine, feces, animal material, insects, bacterial, fungal, botanical

■ Chemical—

■ Physical—fingerprints, footprints, shoe prints, handwriting, firearms, tire marks, tool marks, typewriting

■ Miscellaneous—

Evidence Characteristics

■ Class—common to a _______________of objects or persons

■ Individual—can be identified with a particular _______________or a single source

Which of the examples could be individual evidence?

Forensic Investigations: Include some or all of these seven major activities

1. Recognition—ability to distinguish important evidence from unrelated material

Pattern recognition, Physical property observation, Information analysis, Field testing

2. Preservation—

3. Identification—use of scientific testing

■

■ Physical properties

■ _______________properties

■ Morphological (structural) properties

■ Biological _______________

■ _______________ properties

4. Comparison—class characteristics are measured against those of known standards or controls; if all measurements are equal, then the two samples may be considered to have come from the same source or origin.

5. Individualization—

6. Interpretation—gives meaning to all the information

7. Reconstruction—

■ Inductive and deductive logic

■ Statistical data

■ Pattern analysis

■ Results of laboratory analysis

Dr. Henry Lee—

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