CFC Forensic Science Principles & Investigative Methods 2 — Questions and Answers
Question 1: Which principle states that every contact between two objects leaves a trace that can be detected?
- Locard's Exchange Principle (Correct answer)
- Bertillon's Identification Principle
- Frye Standard
- Daubert Principle
Correct answer: Locard's Exchange Principle
Locard's Exchange Principle holds that any physical contact between two surfaces results in a mutual transfer of material.
Question 2: What is the primary purpose of establishing a chain of custody for physical evidence?
- To expedite laboratory processing
- To document everyone who handled the evidence and ensure its integrity (Correct answer)
- To assign ownership of the evidence to the prosecution
- To determine the monetary value of seized items
Correct answer: To document everyone who handled the evidence and ensure its integrity
Chain of custody documents the chronological history of evidence handling to ensure it has not been tampered with or contaminated.
Question 3: In forensic investigations, what does 'class evidence' refer to?
- Evidence found only at high-profile crime scenes
- Evidence that can narrow an item to a group but not a single source (Correct answer)
- Evidence collected by senior forensic examiners
- Evidence admissible in federal court only
Correct answer: Evidence that can narrow an item to a group but not a single source
Class evidence shares characteristics common to a group of items, such as a shoe print matching a particular brand, but cannot uniquely identify a single source.
Question 4: What is the correct sequence for processing a crime scene?
- Collect, document, secure, analyze
- Secure, document, collect, analyze (Correct answer)
- Analyze, secure, document, collect
- Document, collect, secure, analyze
Correct answer: Secure, document, collect, analyze
Crime scenes must first be secured to prevent contamination, then thoroughly documented before any evidence is collected and later analyzed.
Question 5: Which type of fingerprint pattern is the most common in the general population?
- Arch
- Loop (Correct answer)
- Whorl
- Tented arch
Correct answer: Loop
Loop patterns account for approximately 60–65% of all fingerprints, making them the most frequently encountered pattern type.
Question 6: A forensic investigator discovers luminol-reactive stains at a crime scene. What does a positive luminol reaction indicate?
- The presence of accelerants used in arson
- Possible presence of blood or other peroxidase-containing substances (Correct answer)
- Confirmed presence of human blood only
- Recent cleaning with bleach, ruling out blood
Correct answer: Possible presence of blood or other peroxidase-containing substances
Luminol reacts with the iron in hemoglobin but can also react with other peroxidases, plant matter, and some cleaning agents, so it is presumptive, not confirmatory.
Question 7: What is the role of a forensic consultant's expert report in legal proceedings?
- To replace the need for the expert to testify in court
- To provide a written summary of findings and opinions that can be used by counsel and the court (Correct answer)
- To determine the guilt or innocence of the defendant
- To establish legal precedent for future cases
Correct answer: To provide a written summary of findings and opinions that can be used by counsel and the court
An expert report documents the consultant's methodology, findings, and opinions, serving as a foundation for testimony and allowing opposing counsel to prepare cross-examination.
CFC Forensic Science Principles & Investigative Methods 2
Which principle states that every contact between two objects leaves a trace that can be detected?