JIBC Investigation and Evidence Collection 3 — Questions and Answers
Question 1: What is 'locard's exchange principle' and how does it apply to crime scene investigation?
- Every criminal leaves behind a motive that can be traced
- Every contact between two objects leaves a trace on both (Correct answer)
- Evidence must be exchanged between agencies in joint investigations
- Physical evidence must be logged before being removed from a scene
Correct answer: Every contact between two objects leaves a trace on both
Locard's Exchange Principle states that whenever two objects contact each other, material is exchanged between them, forming the basis of trace evidence collection.
Question 2: Which method is most appropriate for preserving a footwear impression found in soft soil?
- Photographing only and moving on
- Collecting the soil in an evidence bag
- Casting the impression with dental stone or plaster (Correct answer)
- Covering it with a plastic sheet until trial
Correct answer: Casting the impression with dental stone or plaster
Casting with dental stone or plaster creates a three-dimensional permanent record of a footwear impression that can be analyzed and compared.
Question 3: During a vehicle stop investigation, an officer observes contraband in plain view through the window. This is known as:
- Incidental discovery doctrine
- The plain view doctrine (Correct answer)
- Inevitable discovery rule
- Constructive possession finding
Correct answer: The plain view doctrine
The plain view doctrine allows officers to seize evidence without a warrant when they are lawfully present and the incriminating nature of the item is immediately apparent.
Question 4: What is a 'field notes contamination' risk during an investigation?
- Water or weather damage to written notes
- Notes being shared without proper authorization
- Writing facts after hearing other witnesses' accounts (Correct answer)
- Recording information in non-approved formats
Correct answer: Writing facts after hearing other witnesses' accounts
Recording observations after hearing others' accounts risks contaminating an officer's independent recollection with information from other sources.
Question 5: In the context of interviewing suspects, what is the 'PEACE' model primarily used for?
- Establishing rapport with hostile witnesses
- A structured framework for ethical investigative interviewing (Correct answer)
- Assessing the credibility of confession statements
- Documenting use of force during arrest
Correct answer: A structured framework for ethical investigative interviewing
The PEACE model (Preparation, Engage, Account, Closure, Evaluate) provides a structured, ethical framework for investigative interviewing without coercion.
Question 6: When securing a crime scene perimeter, the inner cordon should be:
- As large as possible to include the entire neighborhood
- Set at the minimum boundary needed to protect core evidence (Correct answer)
- Established only after all evidence is collected
- Located at least 500 meters from the incident location
Correct answer: Set at the minimum boundary needed to protect core evidence
The inner cordon should protect the core evidence area without being unnecessarily large, balancing evidence protection with operational needs.
Question 7: What is the significance of 'negative evidence' in an investigation?
- Evidence that proves a suspect's innocence conclusively
- The absence of expected evidence, which is itself informative (Correct answer)
- Testimony that contradicts the prosecution's theory
- Physical evidence that degrades over time
Correct answer: The absence of expected evidence, which is itself informative
Negative evidence refers to the absence of something that would be expected if events occurred as described, which can be as significant as positive findings.
JIBC Investigation and Evidence Collection 3
What is 'locard's exchange principle' and how does it apply to crime scene investigation?