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Quiz: Crime Scene Investigation and Evidence Collection

Test your understanding of crime scene protocols, documentation methods, search patterns, and chain-of-custody procedures with these questions.

1. In the Seven S's of Crime Scene Investigation, why does the word "Secure" appear both first and last in the sequence?

  1. It is a mnemonic device only; both uses refer to the same action of establishing the perimeter
  2. The first "Secure" establishes the perimeter; the last "Secure" refers to packaging and preserving the collected evidence
  3. The repetition indicates that security checks must be logged twice for chain-of-custody purposes
  4. The first "Secure" applies to outdoor scenes; the last applies to indoor scenes with multiple entry points
Show Answer

The correct answer is B. "Secure" appears twice because it addresses two distinct actions at opposite ends of the investigation workflow. The first "Secure" means establishing the crime scene perimeter and stopping contamination. The last "Secure" means securing the collected evidence through proper packaging and initiating chain-of-custody documentation. A failure at either end can destroy a case.

Concept Tested: Seven S's of Crime Scene

2. A first-responding officer arrives at a crime scene and must set the initial perimeter. Which approach is correct?

  1. Set the perimeter at the smallest area containing visible evidence to minimize disruption to the neighborhood
  2. Set the perimeter precisely at the scene boundaries shown in the 911 caller's description
  3. Set the perimeter larger than believed necessary, since it can be shrunk later but contaminated areas cannot be recovered
  4. Set the perimeter based on the number of officers available to guard the tape line
Show Answer

The correct answer is C. The rule of thumb in crime scene investigation is that it is easy to shrink a perimeter once the true scene boundary is understood, but impossible to un-contaminate an area that was trampled before the tape went up. An oversized perimeter has the cost of inconvenience; a perimeter that is too small has the cost of lost or contaminated evidence that may be irreplaceable.

Concept Tested: Crime Scene Perimeter Security

3. Why are witnesses separated from each other before giving statements, as specified in Step 2 of the Seven S's?

  1. Witnesses separated at the scene can be charged as suspects if they resist separation
  2. Separation prevents witness statements from being recorded on the scene log
  3. Human memory is reconstructive, and witnesses who talk together inadvertently merge their recollections
  4. Separation is required under the Fifth Amendment to prevent self-incrimination
Show Answer

The correct answer is C. Human memory is not a recording — it is a reconstruction that is highly susceptible to contamination through social interaction. Witnesses who discuss an event before giving separate statements inadvertently incorporate each other's recollections into their own. Keeping witnesses apart preserves each person's independent account as a separate, uncontaminated data source, which is crucial for building an accurate picture of the event.

Concept Tested: Seven S's of Crime Scene

4. In crime scene photography, what is the correct sequence of photo types, and why does that sequence matter?

  1. Close-up first, then mid-range, then overview — document detail before context is disturbed
  2. Overview first, then mid-range, then close-up — establish spatial context before focusing on individual items
  3. Mid-range first, then close-up, then overview — the most common evidence items are photographed before the full scene
  4. Overview and close-up simultaneously, then mid-range — the most efficient order for large outdoor scenes
Show Answer

The correct answer is B. The correct photographic sequence is overview → mid-range → close-up. Overview photos establish the full scene in context; mid-range photos show the relationship between evidence items and fixed reference points; close-up photos document individual items in maximum detail. This narrative sequence creates a complete, logical visual record from the broad scene down to specific evidence, which courts and analysts rely on to understand spatial relationships.

Concept Tested: Crime Scene Photography

5. Triangulation measurement is preferred over baseline measurement in which scenario?

  1. When the scene is a rectangular indoor room with evidence near the walls
  2. When working with multiple investigators who need to divide measurement duties
  3. When the scene is outdoors or has an irregular shape without parallel walls
  4. When the scene has very small items of evidence that require millimeter precision
Show Answer

The correct answer is C. Triangulation measures the distance from each evidence item to two fixed, permanent reference points. Because any point in two-dimensional space is uniquely determined by its distances to two known points, the method works anywhere — including outdoors or in irregularly shaped spaces — without requiring a straight reference baseline. Baseline measurement is simpler in rectangular rooms but is not adaptable to non-rectangular or outdoor environments.

Concept Tested: Triangulation Measurement

6. An investigator needs to search a large outdoor scene covering approximately 400 square meters with a team of six specialists. Which search pattern is most appropriate?

  1. Spiral inward, because it allows the team to approach the highest-priority central area methodically
  2. Baseline search, because it is the fastest method for large exterior spaces
  3. Zone search, because it divides the large scene among multiple teams and scales efficiently
  4. Grid search, because double-sweep coverage is always required for outdoor scenes
Show Answer

The correct answer is C. The zone search pattern divides the scene into clearly marked sectors, assigns a team to each zone, and deploys multiple teams simultaneously — making it the standard choice for large outdoor scenes (typically over 200 square meters) and for teams with specialists whose expertise can be matched to specific zones. The grid search is more thorough but is slower and better suited to high-priority scenes with fewer searchers.

Concept Tested: Zone Search Pattern

7. Which type of physical evidence is considered the physical embodiment of Locard's Exchange Principle and is most easily destroyed by contamination?

  1. Documentary evidence, because paper absorbs chemical contaminants easily
  2. Biological evidence, because DNA degrades quickly in warm environments
  3. Impression evidence, because footwear impressions can be obscured by additional footsteps
  4. Trace evidence, because it consists of microscopic transferred materials that are invisible and easily disturbed
Show Answer

The correct answer is D. Trace evidence — microscopic or near-microscopic material transferred by contact, such as fibers, glass fragments, and soil — is the physical embodiment of the Locard Exchange Principle. It is the category most easily overlooked because it is invisible to the unaided eye, and it is most easily destroyed by contamination because any additional contact at the scene can add, remove, or mix the transferred materials.

Concept Tested: Trace Evidence

8. Why should wet biological evidence (such as blood-soaked fabric) never be packaged in a plastic bag for long-term storage?

  1. Plastic bags are not tamper-evident and cannot be properly sealed for court admission
  2. Airtight plastic traps moisture, promoting mold growth that degrades DNA within 24–48 hours
  3. Plastic generates static electricity that can damage cellular material in the sample
  4. Court regulations require all biological evidence to be in transparent packaging for chain-of-custody verification
Show Answer

The correct answer is B. Airtight plastic packaging traps moisture around wet biological evidence, creating ideal conditions for mold growth that can degrade DNA within 24–48 hours. Paper packaging allows moisture to escape — it breathes — so the evidence air-dries and is preserved. This is one of the most common and damaging packaging errors at crime scenes. The correct packaging for wet biological evidence is always paper (bags, envelopes, or boxes) before any plastic is used.

Concept Tested: Evidence Packaging Materials

  1. A gap triggers automatic retesting by an independent laboratory before the evidence is admitted
  2. A gap requires the prosecutor to provide a sworn affidavit explaining the missing transfer period
  3. A gap gives the defense grounds to argue the evidence may have been contaminated or tampered with, potentially leading to exclusion
  4. A gap is considered a minor administrative error and does not affect evidence admissibility
Show Answer

The correct answer is C. A gap in the chain of custody represents an unaccounted period during which the evidence's integrity cannot be verified. Defense attorneys use such gaps to argue that the evidence may have been contaminated, altered, or substituted — and a judge may exclude the evidence entirely if the chain is not adequately documented. The chain of custody is described in the chapter as "the legal immune system of physical evidence."

Concept Tested: Chain of Custody

10. The druggist fold technique is used to package which type of evidence, and why is this technique preferred over a standard envelope?

  1. Sharp objects, because the multiple layers prevent puncture of the outer container
  2. Digital devices, because the folds create an electromagnetic shield preventing remote wiping
  3. Wet biological fluids, because the folds create an airtight seal that prevents contamination
  4. Loose trace evidence such as fibers and glass fragments, because multiple folds prevent fine particles from escaping through any single opening
Show Answer

The correct answer is D. The druggist fold (also called a pharmaceutical fold or bindle) uses a series of four overlapping folds to create a secure, self-sealing paper packet that contains loose trace evidence — fibers, glass fragments, hair, soil — without allowing fine particles to escape through the single opening of a standard envelope. The multiple folds create a series of barriers, keeping even microscopic particles contained until laboratory analysis.

Concept Tested: Druggist Fold Technique