Investigation and Evidence Collection Flashcards

What is 'locard's exchange principle' and how does it apply to crime scene investigation?

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.

Which method is most appropriate for preserving a footwear impression found in soft soil?

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.

During a vehicle stop investigation, an officer observes contraband in plain view through the window. This is known as:

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.

What is a 'field notes contamination' risk during an investigation?

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.

In the context of interviewing suspects, what is the 'PEACE' model primarily used for?

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.

When securing a crime scene perimeter, the inner cordon should be:

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.

What is the significance of 'negative evidence' in an investigation?

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.