CFL Key & Lock Examination 3

Question 1

Which evidence of forced entry in a pin tumbler lock is MOST associated with bumping attacks?

Accepted Answer

Uniformly distributed impact marks on all pin chambers

Answer

Bump keys cause the driver pins to momentarily jump simultaneously, leaving characteristic impact marks across all pin chambers rather than sequential picking marks.

Question 2

A forensic locksmith examines a padlock shackle and finds transverse (horizontal) saw marks. This evidence MOST suggests:

Accepted Answer

Cutting of the shackle with a saw or bolt cutters

Answer

Transverse saw marks on a shackle indicate it was cut with a hacksaw or similar tool, a common forced entry method targeting the exposed shackle.

Question 3

What forensic significance do 'witness marks' have in lock examination?

Accepted Answer

They show contact points between moving parts, revealing manipulation history

Answer

Witness marks are transfer impressions left where two parts have contacted each other, revealing how and whether components were manipulated.

Question 4

When a lock plug shows extensive circumferential scratching around its outer diameter, a CFL would MOST likely conclude:

Accepted Answer

The plug was rotated against the shell without a key, suggesting picking or bypass

Answer

Circumferential scratches around the plug's outer diameter indicate the plug rotated without a proper key, which occurs during picking, decoding, or bypass attempts.

Question 5

In a forensic examination, 'false set' in a lock refers to:

Accepted Answer

A secondary rotation point that occurs during picking when spools or serrated pins are present

Answer

A false set is the slight plug rotation felt by a picker when serrated or spool pins partially set, which is a key indicator that anti-pick pins are present in the lock.

(CFL) Certified Forensic Locksmith Practice Test

(CFL) Certified Forensic Locksmith Practice Test

CFL Key & Lock Examination 3