Forensic Analysis & Evidence Handling Flashcards

A forensic locksmith is asked to examine a safe lock that may have been manipulated. The FIRST step before disassembly should be:

Answer: Photograph and document the lock exterior and dial position in place

Thorough documentation before any disassembly preserves the original state of evidence, including dial position which may indicate manipulation.

Which characteristic distinguishes a 'forced key' entry from a 'correct key' entry on a pin tumbler lock?

Answer: Forced key entry causes false shear lines and splintered pin surfaces; correct key entry does not

A forced or wrong key creates false shear lines, shearing or splintering pins where they should not separate, unlike a correct key.

When using casting compounds (such as Mikrosil or Durocast) to preserve toolmarks in a lock, the forensic examiner should:

Answer: Photograph the marks first, then apply the compound without disturbing the marks

Photography must precede casting because the casting process can slightly displace trace evidence, making original photographic documentation essential.

A forensic locksmith finds a lock with scoring marks on the top of the plug face and the shell. This pattern is MOST consistent with:

Answer: A drill attack targeting the shear line from the front

Scoring marks across the plug face and shell at the shear line are the hallmark of a drill attack designed to destroy the pin tumblers.

In court testimony, a forensic locksmith who overstates certainty beyond what the evidence supports risks:

Answer: Being impeached on cross-examination and undermining the entire case

Overstating certainty exposes an expert to impeachment, which can discredit all of their testimony and harm the case's outcome.

A 'control' lock — one of the same make, model, and configuration — is included in a forensic examination because:

Answer: It establishes a baseline of normal manufacturing marks and wear for comparison to the questioned lock

A control lock establishes what normal manufacturing artifacts and expected wear look like so they can be distinguished from toolmarks left during manipulation.

Which of the following actions would MOST seriously compromise the integrity of a lock submitted as forensic evidence?

Answer: Inserting any key into the lock cylinder before documentation is complete

Inserting a key can deposit new marks, displace trace evidence, and alter the positions of internal components, irreversibly contaminating the evidence.