CFC Forensic Science Principles & Investigative Methods 4 — Questions and Answers
Question 1: In forensic entomology, blow fly (Calliphoridae) succession on a corpse is primarily used to estimate:
- The victim's age at time of death
- The minimum postmortem interval (Correct answer)
- The cause of death
- Whether the death occurred indoors or outdoors
Correct answer: The minimum postmortem interval
Forensic entomologists use the developmental stage and species of insects colonizing remains to estimate the minimum time since death, known as the postmortem interval.
Question 2: What is the 'Frye standard' as applied in some U.S. jurisdictions for expert testimony?
- Expert witnesses must hold a doctoral degree
- Scientific evidence must be generally accepted in the relevant scientific community (Correct answer)
- All expert opinions must be supported by peer-reviewed publications
- Experts must testify without compensation to avoid bias
Correct answer: Scientific evidence must be generally accepted in the relevant scientific community
The Frye standard, from Frye v. United States (1923), requires that scientific evidence be generally accepted by the relevant scientific community before it can be admitted.
Question 3: During a fire investigation, what does the presence of low burn patterns and multiple points of origin most strongly suggest?
- Spontaneous combustion
- Arson with intentional use of accelerants (Correct answer)
- Electrical malfunction
- Accidental fire from a single ignition source
Correct answer: Arson with intentional use of accelerants
Low burn patterns near the floor and multiple origin points are classic indicators that an accelerant was poured at several locations to set a fire deliberately.
Question 4: Which of the following BEST describes the role of forensic toxicology in a death investigation?
- Determining the mechanism of injury from physical trauma
- Identifying and quantifying drugs, poisons, or alcohol in biological specimens (Correct answer)
- Reconstructing the sequence of events at a crime scene
- Estimating time of death using insect evidence
Correct answer: Identifying and quantifying drugs, poisons, or alcohol in biological specimens
Forensic toxicology analyzes biological fluids and tissues to detect and measure the presence of substances that may have contributed to or caused death.
Question 5: What is 'substrate control' in the context of forensic trace evidence collection?
- A method of controlling access to the crime scene
- A sample of the surface material from near the evidence to detect background contamination (Correct answer)
- A software tool for analyzing trace evidence databases
- A calibration standard used in scanning electron microscopy
Correct answer: A sample of the surface material from near the evidence to detect background contamination
A substrate control is collected from an area adjacent to the evidence to determine whether detected materials are background contamination rather than evidence of interest.
Question 6: In forensic anthropology, the term 'biological profile' refers to:
- A DNA profile derived from skeletal remains
- An estimation of the decedent's sex, age, ancestry, and stature from skeletal analysis (Correct answer)
- A psychological assessment of the likely perpetrator
- A toxicological report based on bone marrow analysis
Correct answer: An estimation of the decedent's sex, age, ancestry, and stature from skeletal analysis
Forensic anthropologists construct a biological profile by analyzing skeletal features to estimate the four major parameters: sex, age at death, ancestry, and stature.
Question 7: An investigator is evaluating a gunshot residue (GSR) sample. Which element combination is considered most specific for identifying primer-derived GSR?
- Carbon, hydrogen, and oxygen
- Lead, barium, and antimony (Correct answer)
- Copper, zinc, and nickel
- Silicon, aluminum, and iron
Correct answer: Lead, barium, and antimony
Particles containing lead (Pb), barium (Ba), and antimony (Sb) together are considered highly characteristic of primer-derived GSR when detected by scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDX).
CFC Forensic Science Principles & Investigative Methods 4
In forensic entomology, blow fly (Calliphoridae) succession on a corpse is primarily used to estimate: