Key & Lock Examination Flashcards

A forensic locksmith finds that the driver pins in a cylinder are a mix of standard and spool pins. This is MOST significant because:

Answer: Spool pins are anti-pick features that leave specific forensic marks when manipulated

Spool driver pins create a false set during picking attempts and leave distinctive rotation marks when manipulated, providing forensic evidence of a picking attack.

When comparing two keys to determine if one was used to make the other, which measurement is LEAST useful forensically?

Answer: Bow (head) shape and size

The bow shape is irrelevant to lock function and is not transferred during duplication; only blade dimensions determine if one key was copied from another.

A CFL is examining a lever lock from a safe. Which evidence BEST indicates a lever manipulation attack rather than forced entry?

Answer: Fine scratches and tool marks on the lever gates and fence

Lever manipulation (picking) leaves fine scratches and contact marks on the lever gates and fence as the manipulator probes for the correct lever height.

What role does photographic documentation play in key and lock forensic examination?

Answer: It provides a permanent visual record of toolmarks and wear patterns before any destructive analysis

Photographic documentation preserves the as-found condition of toolmarks and evidence that may be altered or destroyed during subsequent physical examination.

In a high-security Medeco-type lock, the rotating pins serve what forensic significance?

Answer: They leave rotation marks that indicate whether the correct key angle was used or a bypass was attempted

Medeco rotating pins must be aligned to the correct angle for the sidebar to retract; manipulation attempts leave characteristic rotation marks showing improper angle probing.

When a forensic locksmith identifies 'shear line scoring,' this finding indicates:

Answer: The lock plug rotated without proper pin alignment, suggesting picking or bypass

Shear line scoring occurs when the plug rotates while pins are not perfectly aligned, which happens during picking or bypass attempts that force plug rotation without correct key bitting.

A CFL is asked to determine if a vehicle's ignition lock was hot-wired after a theft. The MOST relevant forensic evidence in the lock itself would be:

Answer: Toolmarks consistent with bypass tools inside the steering column lock

Hot-wiring typically requires bypassing or disabling the steering column lock, leaving toolmarks from pry bars, picks, or bypass tools on the cylinder or column housing.