Forensic Science Chapter 2 Flashcards

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Questions and Answers

Explain the difference between testimonial evidence and physical evidence.

Testimonial evidence is a statement made under oath and is direct; physical evidence can be any object or material relevant to a crime and is indirect.

List three factors that may affect the memory of an eyewitness in recounting a crime.

Whether the witness already knew the accused and their relationship. 2. How much time has passed between the offense and the identification. 3. The interviewing techniques or how information was retrieved.

List five types of physical evidence.

Rubber material, documents, fibers, soil, and glass.

How is circumstantial evidence different from physical evidence?

Circumstantial evidence is based on suggestion rather than personal knowledge or observation. Signup and view all the answers

Give three examples of transient evidence and explain why it might be transient.

<ol> <li>Odors because they fade away over time. 2. Temperature of an object as it changes with its surroundings. 3. Imprints and indentations in sand or food because they can quickly disappear due to wind and nature.</li> </ol> Signup and view all the answers

Give three examples of conditional evidence and explain why it is conditional.

<ol> <li>Skid marks because they indicate a car had to have a burnout or brake hard. 2. An open garage door suggests someone opened it. 3. Body position implies an event had to occur for the body to be in a specific location.</li> </ol> Signup and view all the answers

Which is generally more reliable, physical evidence or testimonial evidence?

Physical evidence. Signup and view all the answers

What is meant by indirect evidence?

Indirect evidence is evidence providing only a basis for inference about a disputed fact and does not prove a fact. Signup and view all the answers

What significant type of evidence was used to convict Coral Eugene Watts?

Witness testimony. Signup and view all the answers

What did prosecutors want to reopen Coral Eugene Watts's case after so many years?

They were worried he was going to kill more people after being released. Signup and view all the answers

What is the significance of the Ronald Cotton case?

DNA testing was used to find the actual criminal. Signup and view all the answers

State the difference between class and individual evidence.

Individual evidence is related to a single source, while class evidence can be associated with a group of items that share properties. Signup and view all the answers

Can class evidence be used to link a suspect with certainty to a victim or crime? Can individual evidence?

Class evidence cannot; individual evidence can. Signup and view all the answers

Explain how class evidence may be useful.

Class evidence may be used to eliminate a certain group of suspects. Signup and view all the answers

What is direct evidence?

Evidence that stands on its own to prove an alleged fact. Signup and view all the answers

Where is physical evidence found and collected?

At a crime scene. Signup and view all the answers

Why is physical evidence important? What can it prove?

It can prove that a crime has been committed, prove or falsify a witness testimony, link a suspect to a victim, and allow investigators to reconstruct a crime. Signup and view all the answers

What is meant by control sample?

A control sample is material similar to questioned and known samples, used to validate test methods and procedures. Signup and view all the answers

How can class evidence be used to narrow a field of suspects?

It can eliminate a group of suspects that do not meet the requirements for the evidence. Signup and view all the answers

Explain how individualized evidence can have probative value.

It shows that the evidence is unique to a particular individual. Signup and view all the answers

Explain how class evidence can have probative value.

It can eliminate a suspect or a group of suspects being tried. Signup and view all the answers

What is the significance of the Richard Crafts case?

Thousands of forensic tests occurred with little evidence; forensic science was crucial for the conviction. Signup and view all the answers

Study Notes

Forensic Evidence Overview

Testimonial Evidence: Statements made under oath, direct in nature.
Physical Evidence: Tangible objects/materials relevant to a crime, indirect in nature.

Eyewitness Memory Factors

Relationship with accused can influence memory reliability.
Time elapsed between crime and identification affects recollection.
Interviewing techniques impact the recall of details by the witness.

Types of Physical Evidence

Includes rubber materials, documents, fibers, soil, and glass.

Circumstantial vs. Physical Evidence

Circumstantial Evidence: Based on suggestion rather than personal observation or knowledge.

Transient Evidence Examples

Odors: Fade over time.
Temperature: Changes with environmental conditions.
Imprints/Indentations: Can quickly disappear due to natural elements.

Conditional Evidence Examples

Skid Marks: Indicate vehicle maneuvering behaviors.
Open Garage Door: Suggests prior human interaction.
Body Position: Implies a specific event occurred.

Reliability of Evidence

Physical evidence is generally more reliable than testimonial evidence.
Physical evidence substantiates witness statements and helps reconstruct crimes.

Indirect Evidence

Provides a basis for inference without directly proving a fact.

Coral Eugene Watts Case

Primarily convicted through witness testimony from three survivors.

Reopening Watts' Case

Concerns raised about potential for additional violence post-release.

Ronald Cotton Case Significance

Landmark case utilizing DNA testing to identify the actual offender.

Class vs. Individual Evidence

Individual Evidence: Linked to a single source.
Class Evidence: Associated with groups that share common characteristics.

Linkage Certainty

Class evidence cannot link a suspect with certainty, while individual evidence can.

Utility of Class Evidence

Helps narrow down and eliminate suspect groups.

Direct Evidence Definition

Stands alone to establish an alleged fact.

Physical Evidence Collection

Found and collected at crime scenes.

Importance of Physical Evidence

Proves a crime occurred, corroborates or refutes witness testimony, links suspects to victims, aids crime reconstruction.

Control Sample Explanation

Material similar to questioned and known samples, used to validate testing methods.

Narrowing Suspects with Class Evidence

Eliminates groups of suspects who do not match evidence characteristics.

Individualized Evidence and Probative Value

Unique to an individual, increasing its significance in linking to a crime.

Class Evidence and Probative Value

Useful in suspect elimination during trials.

Richard Crafts Case Significance

Demonstrated extensive forensic tests with minimal evidence; highlighted the pivotal role of forensic science in securing convictions.

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Description

Test your knowledge with flashcards focusing on Chapter 2 of Forensic Science. This quiz covers key concepts including testimonial vs. physical evidence and factors affecting eyewitness memory. Perfect for reinforcing your understanding of crucial forensic principles.