CMI Evidence Collection & Forensic Analysis 2 — Questions and Answers
Question 1: When photographing a vessel casualty scene, what is the correct sequence for documenting physical evidence?
- Close-up shots first, then wide-angle overviews
- Wide-angle overview shots first, then progressively closer detail shots (Correct answer)
- Random order is acceptable as long as all evidence is captured
- Photograph only damaged areas to conserve storage
Correct answer: Wide-angle overview shots first, then progressively closer detail shots
Proper forensic photography follows a wide-to-close sequence: overview, mid-range, and close-up shots to establish context before recording detail.
Question 2: A marine investigator discovers an oily residue on the bilge pump discharge. Which chain of custody action is most critical at this point?
- Note the location in a field log and collect a sample later
- Collect the sample immediately, seal and label it with date, time, location, and collector identity (Correct answer)
- Photograph the residue and leave it in place for the vessel owner to preserve
- Request the USCG collect the sample to avoid civil liability
Correct answer: Collect the sample immediately, seal and label it with date, time, location, and collector identity
Chain of custody requires immediate collection, proper sealing, and complete labeling at the moment of discovery to prevent contamination or tampering.
Question 3: What type of fracture pattern in a vessel's hull plating is most indicative of an internal explosion rather than a collision?
- Inward-directed petaling with deformation pointing toward the explosion source
- Outward-directed petaling with deformation radiating away from the blast center (Correct answer)
- Smooth, linear crack running parallel to the keel
- Uniform dimpling across a large surface area
Correct answer: Outward-directed petaling with deformation radiating away from the blast center
Internal explosions push hull material outward, creating outward-petaling fractures with deformation radiating away from the blast's origin point.
Question 4: During a fire investigation aboard a vessel, investigators find the deepest char at the lowest point of a V-pattern burn. What does this most likely indicate?
- The fire spread from above and burned downward
- The fire originated near the base of the V-pattern, consistent with a low burn origin (Correct answer)
- The fire was caused by spontaneous combustion in the bilge
- Water suppression during firefighting caused the char pattern
Correct answer: The fire originated near the base of the V-pattern, consistent with a low burn origin
A V-pattern with the deepest char at its base indicates a low point of origin, as fire burns upward and outward from its ignition source.
Question 5: When collecting water samples as evidence in a pollution investigation, how should samples be stored to preserve their evidentiary value?
- In standard plastic bottles at ambient temperature
- In amber glass containers, refrigerated at 4°C, with appropriate preservatives per analyte (Correct answer)
- In clear glass bottles exposed to sunlight to allow natural oxidation
- Frozen immediately after collection to prevent bacterial growth
Correct answer: In amber glass containers, refrigerated at 4°C, with appropriate preservatives per analyte
Amber glass prevents photodegradation, refrigeration at 4°C slows microbial activity, and preservatives are required depending on the specific analytes being tested.
Question 6: A marine investigator is documenting a grounding incident. What information is essential when sketching the scene at the point of first contact?
- Only the compass bearing of the vessel at grounding
- Position coordinates, water depth, bottom composition, tide stage, and direction of vessel travel (Correct answer)
- The name of the pilot on watch and vessel registration number only
- GPS track log data exclusively, as it supersedes hand-drawn sketches
Correct answer: Position coordinates, water depth, bottom composition, tide stage, and direction of vessel travel
An accurate grounding scene sketch requires position, depth, bottom type, tide stage, and vessel heading to reconstruct how and why the vessel struck bottom.
Question 7: Which document is the primary forensic record of a vessel's movements and crew actions leading up to a marine casualty?
- Port state control inspection report
- Official deck logbook maintained by the officer of the watch (Correct answer)
- Vessel traffic service (VTS) radar replay
- Insurance survey report
Correct answer: Official deck logbook maintained by the officer of the watch
The official deck logbook is the contemporaneous, legally required record of navigational events, weather, and crew actions maintained throughout the voyage.
CMI Evidence Collection & Forensic Analysis 2
When photographing a vessel casualty scene, what is the correct sequence for documenting physical evidence?