Forensics Chapter 3 Flashcards

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Questions and Answers

What is the definition of physical evidence?

Any object that can establish a crime that has been committed or link a victim to a crime.

What are two reasons why physical evidence is more reliable than eyewitness testimony?

Can prove a crime has been committed (correct)

Can link suspects with victim (correct)

Less subjective

Always accurate

List six types of physical evidence derived from human or other animal sources commonly found at crime scenes.

Hair, Saliva, Semen, Fingerprints, Blood, Organs.

List six types of physical evidence that are not derived from human or animal sources.

Impressions, Ink, Fibers, Glass, Explosives, Documents. Signup and view all the answers

What is the general rule of law when identifying evidence at a crime scene?

Evidence collected must be relevant to be admissible. Signup and view all the answers

What are two conditions for the relevance of physical evidence to be admissible in court?

Material = pertains to particular crime; Probative = must prove something. Signup and view all the answers

Define physical and nonphysical evidence.

Nonphysical - verbal testimony about the crime; Physical - tangible objects. Signup and view all the answers

Define real and demonstrative evidence.

Demonstrative - evidence used to help create sketches; Real - evidence generated by criminal activity found at the crime scene. Signup and view all the answers

Define known and unknown evidence.

Known - objects whose source is known; Unknown - collected from a source with unknown origins. Signup and view all the answers

Define individual and class characteristics.

Individual - evidence from one source; Class - evidence from several sources. Signup and view all the answers

What are two examples of physical evidence?

Fingerprints, Hair. Signup and view all the answers

What are two examples of class evidence?

White cotton, Blue denim. Signup and view all the answers

What is testimonial evidence?

Evidence in the form of witness statements made under oath in court. Signup and view all the answers

What is the difference between testimonial and physical evidence?

Testimonial - made from a witness in court; Physical - anything tangible. Signup and view all the answers

What is one factor that can affect eyewitness testimony?

Characteristics of the witness. Signup and view all the answers

What is the name of the computer program used by police agencies to generate a composite of a suspect?

FACES. Signup and view all the answers

Give two examples of biological evidence.

Semen, Saliva. Signup and view all the answers

Give two examples of chemical evidence.

Fibers, Glass. Signup and view all the answers

Give two examples of physical evidence.

Hair, Drugs. Signup and view all the answers

Give two examples of impression evidence.

Teeth marks, Tire marks. Signup and view all the answers

Give two examples of manufactured evidence.

Garbage bags, Clothes. Signup and view all the answers

Define transient evidence and provide one example.

Transient evidence - temporary evidence that can be easily changed or lost; Example: Temporary markings. Signup and view all the answers

Define pattern evidence and provide one example.

Pattern - evidence produced by direct contact between people or objects; Example: Shoe prints. Signup and view all the answers

List and define the two methods used by forensic scientists when examining physical evidence.

Identification - process of determining a substance's physical ability; Comparison - process of determining common origins. Signup and view all the answers

To permit positive identification, what two conditions must testing procedures meet?

Testing procedures must yield characteristic results; Number & type of tests must sufficiently exclude other substances. Signup and view all the answers

Describe two steps in the process of comparison. What question does each step attempt to answer?

Select properties to compare; Draw conclusions about origins. Signup and view all the answers

Define the product rule.

Determines how frequent a certain combination of characteristics occurs in a population. Signup and view all the answers

What is the greatest weakness of class evidence? List two factors that contribute to this weakness.

Inability of examiner to assign exact values; Influences of multiple sources. Signup and view all the answers

Which country has the largest database of evidence?

England. Signup and view all the answers

What does IAFIS stand for?

Integrated Automated Fingerprint Identification System. Signup and view all the answers

Study Notes

Physical Evidence Overview

Physical evidence includes any object that can demonstrate that a crime has occurred or link a victim to a suspect.
It is typically more reliable than eyewitness testimony due to its ability to directly connect individuals to crimes.

Types of Physical Evidence

Derived from human or animal sources:
- Hair
- Saliva
- Semen
- Fingerprints
- Blood
- Organs
Not derived from biological sources:
- Impressions
- Ink
- Fibers
- Glass
- Explosives
- Documents

Legal Relevance of Evidence

Evidence must be relevant to be admissible in court.
Relevance is determined by two conditions:
- Maternal: relates to a specific crime
- Probative: demonstrates something significant

Evidence Classification

Physical evidence represents tangible items, while nonphysical evidence includes verbal testimonies.
Real evidence is found at crime scenes, whereas demonstrative evidence aids in illustrating other evidence.
Known evidence has a known source at collection; unknown evidence does not.

Characteristics of Evidence

Individual characteristics are unique to a specific source (e.g., nuclear DNA), while class characteristics are common across multiple sources (e.g., blue denim).
Class evidence can provide context but lacks the precision of individual evidence.

Types of Testimonial Evidence

Testimonial evidence consists of witness statements made under oath.
Eyewitness testimony can be affected by witness characteristics.

Tools and Programs in Forensics

The FACES program is used by law enforcement to generate suspect composites.
Forensic analysis includes identifying and comparing physical evidence through established procedures.

Evidence Examination Procedures

Identification determines a substance’s physical attributes to distinguish it from others.
Comparison assesses whether specimens share a common origin through selected properties.

Key Concepts in Evidence Analysis

The product rule calculates the frequency of specific characteristic combinations in a population.
Class evidence poses limitations due to challenges in assigning exact values to its comparisons.

Global Context

England maintains the largest forensic database, enhancing criminal investigation capabilities.
IAFIS (Integrated Automated Fingerprint Identification System) is critical for fingerprint matching and identification.

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Description

Test your knowledge on physical evidence in forensics with these flashcards. This chapter explores definitions, reliability, and types of physical evidence significant for crime investigation. Enhance your understanding of how physical evidence plays a crucial role in linking victims to crimes.