Forensic Evidence Types Overview

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Questions and Answers

What type of blood spatter is present on the assailant's face when a victim is stabbed in the chest and coughs?

Expirated

What type of bloodstain pattern describes the overall bloodstain below?

Arterial Gush

What type of bloodstain pattern is represented when a suspect steps in blood and leaves footprints?

Transfer

What best describes an instrumental bloodstain pattern?

The spatter that results from a victim being beaten with a baseball bat Signup and view all the answers

Which type of drug creates an excitatory condition within the body?

Amphetamines Signup and view all the answers

When an individual needs a drug to maintain a sense of emotional well-being, this describes which of the following?

Both A and B Signup and view all the answers

Which of the following does not represent an application of forensic toxicology?

Workplace drug testing Signup and view all the answers

What is referred to as the amount of a chemical entering the body?

Dose Signup and view all the answers

What describes only qualitative results of a toxicology screening?

The testing revealed the presence of cocaine Signup and view all the answers

Which drug is responsible for the majority of single-car fatalities?

Alcohol Signup and view all the answers

Which drug results in a decreased heart rate, depressed respiration, and sleepiness?

Morphine Signup and view all the answers

All individuals will react to the same dose of a substance in the same way.

False Signup and view all the answers

Which body fluid/tissue is most typically used in workplace drug testing?

Urine Signup and view all the answers

If a toxicant is taken with the intent to commit suicide, this refers to the substance being taken how?

Deliberately Signup and view all the answers

What does the term 'nature of exposure' refer to in relation to toxicity?

How the substance enters the body Signup and view all the answers

What is the gradual cooling of the body after death called?

Algor mortis Signup and view all the answers

Which of the following is not a manner of death?

Heart attack Signup and view all the answers

What is the difference between class and individual evidence?

Class evidence places the suspect into a group (e.g., blood type). Individual evidence narrows a suspect down to a single individual (e.g., anything containing nuclear DNA). Signup and view all the answers

Provide examples of class evidence.

Blood type. Signup and view all the answers

Provide examples of individual evidence.

Anything that contains nuclear DNA. Signup and view all the answers

Describe the importance of blood spatter evidence in a crime scene investigation.

It can reveal the type of weapon used, the time of the crime, and provide details on the manner of the crime. Signup and view all the answers

Describe the importance of fingerprint evidence in a crime scene investigation.

Fingerprints can provide class evidence and may act as individual evidence if enough detail is retrieved. Signup and view all the answers

How is blood evidence used in forensics?

It is collected, categorized, and compared; blood typing provides class evidence, whereas DNA analysis provides individual evidence. Signup and view all the answers

What are sources of DNA found at crime scenes?

Body fluid, hair, skin, and semen. Signup and view all the answers

What are the 5 classifications of drugs?

Schedule 1, Schedule 2, Schedule 3, Schedule 4, Schedule 5. Signup and view all the answers

What is the difference between acute and chronic poisoning?

Acute poisoning is caused by a high dose over a short period; chronic poisoning is caused by lower doses over a long period. Signup and view all the answers

How are fingerprints categorized?

Latent, patent, or plastic. Signup and view all the answers

Can a single fingerprint ridge that splits into three distinct ridges be called trifurcation?

True Signup and view all the answers

What does the term 'Rh antigen' refer to?

It refers to the protein that determines whether blood type is positive or negative. Signup and view all the answers

Which of the following can be considered a universal blood donor for the ABO system?

Type O Signup and view all the answers

Which light rays are utilized to enhance the presence of bodily fluids during an investigation?

UV Light Signup and view all the answers

Which statement best describes a passive bloodstain pattern?

Blood dripping directly downward Signup and view all the answers

Can two parents with type A blood have a child with type O blood?

True Signup and view all the answers

How long is the telogen phase of hair growth?

2-6 months Signup and view all the answers

Match the following drugs with their classifications:

Marijuana = Schedule 1 Cocaine = Schedule 2 Steroids = Schedule 3 Xanax = Schedule 4 Robitussin = Schedule 5 Signup and view all the answers

The active phase of hair growth is called _____

Anagen Signup and view all the answers

What type of fingerprint pattern has no deltas or cores?

Arch Signup and view all the answers

Fingerprints can change over time.

False Signup and view all the answers

A crime scene is protected and secured for what purpose?

To ensure that individuals do not interfere with and contaminate a crime scene. Signup and view all the answers

Who is credited with conducting the first forensic criminal investigation?

Alphonse Bertillion Signup and view all the answers

Study Notes

Class vs. Individual Evidence

Class evidence categorizes a suspect into a broader group, such as blood type.
Individual evidence identifies a specific individual, such as DNA from a blood sample.

Importance of Various Evidence Types

Blood Spatter: Reveals weapon type, crime timing, and manner through droplet patterns, angle of impact, and area of origin.
Fingerprints: Provide class evidence through pattern types (loop, arch, whorl); individual evidence through unique ridge detail.
Hair: Analyzed for DNA and microscopic characteristics, determining its origin and linking to individuals.
Fibers: Can establish links between suspects and victims; analyzed for origin based on matching fibers.

Blood Evidence in Forensics

Blood typing offers class evidence, while DNA STR analysis provides individual evidence of consistency with a suspect.
Collection involves using sterile cloths for liquid blood and placing dried blood items in paper bags.
Blood spatter analysis defines the origin, direction, size of droplets, and weapon type used in an assault.

DNA in Forensics

DNA is critical for linking individuals to crime scenes; extreme reliability helps in identification.
Collected from body fluids, hair, skin, and semen; contamination prevention is crucial during handling.
DNA can be planted to mislead investigations; also used to identify victims.
Short Tandem Repeats (STR) are regions of DNA analyzed for identifying individuals.

Drug Toxicology

Toxicology: Study of the effects of drugs and toxins on the body, assessed following fatalities.
Drug Classifications:
- Schedule 1: No medical use (e.g., Marijuana).
- Schedule 2: High abuse potential (e.g., Cocaine).
- Schedule 3: Moderate abuse potential (e.g., Steroids).
- Schedule 4: Low abuse potential (e.g., Xanax).
- Schedule 5: Widely used for medical purposes (e.g., Robitussin).
Acute vs. Chronic Poisoning: Acute is high dose, chronic is low dose over time. Key factors include dose and exposure duration.

Fingerprints in Forensics

Unique and unchanged throughout life, fingerprints help in identifying individuals.
Types: latent, patent, and plastic; collected using various techniques, enhancing visibility with carbon powder.
Reliability issues exist, as examiners may misinterpret patterns (loops, arches, whorls).

Crime Scene Analysis Steps

First responders secure the scene and separate witnesses.
Analysts photograph the scene, sketch layout, and search for evidence using proper collection protocols.
Evidence is air dried and packaged securely, with detailed documentation for chain of custody.

Eyewitness and Biological Evidence Interpretation

Numerous factors affect eyewitness testimony, including age and mental state.
Biological evidence includes fluids like blood but excludes fingerprints.

Blood Evidence Characteristics

Blood type O is the universal donor in the ABO system.
Red blood cells carry oxygen; plasma is the liquid component of blood.
Respective blood types can be inherited based on parental genotypes.

Additional Forensics Concepts

Crime scenes are secured to prevent contamination.
Instruments like UV light enhance visibility of bodily fluids.
Understanding bloodstain patterns aids in reconstructing crime events (passive, transfer, expirated).

Impacts of Drugs and Toxins

Alcohol associated with a significant number of traffic fatalities.
Morphine typically decreases heart rate and respiratory function.
Dependence can be physical or psychological; workplace drug testing largely focuses on urine samples.

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Description

This quiz covers the distinctions between class and individual evidence in forensic science. You'll explore the importance of various types of evidence, including blood spatter, fingerprints, hair, and fibers. Test your knowledge on how these pieces of evidence can link suspects to crimes.