CFL Lock Identification & Key Systems 3 — Questions and Answers
Question 1: During a crime scene examination, a deadbolt cylinder shows a cracked plug and metal burrs on the plug face. The most likely forced entry method is:
- Lock picking
- Key bumping
- Cylinder pulling (Correct answer)
- Impressioning
Correct answer: Cylinder pulling
Cylinder pulling uses a slide hammer or dent puller to physically extract the plug from the cylinder, causing cracking, burring, and deformation of the plug face.
Question 2: A warded lock uses internal obstructions (wards) to prevent incorrect keys from turning. Forensically, what is the primary weakness a locksmith would note?
- Wards can be decoded by X-ray analysis only
- A skeleton key with all non-essential metal removed can bypass most ward configurations (Correct answer)
- Ward locks require specialized picking tools unavailable to criminals
- The number of wards makes key duplication nearly impossible
Correct answer: A skeleton key with all non-essential metal removed can bypass most ward configurations
Skeleton keys have material filed away to avoid the wards, allowing them to rotate the bolt mechanism in many warded locks regardless of specific ward patterns.
Question 3: High-security lock standard ANSI/BHMA Grade 1 specifies resistance to which attack that is particularly relevant in forensic cases?
- Electromagnetic field disruption
- Pick and tension tool manipulation (Correct answer)
- Chemical solvent degradation
- Thermal expansion attacks
Correct answer: Pick and tension tool manipulation
ANSI/BHMA Grade 1 standards include testing for pick resistance, among other physical attacks, making this rating forensically relevant for assessing expected attack resistance.
Question 4: A locksmith examines a padlock shackle with a clean, flat cut through the metal. This pattern indicates the use of:
- A bolt cutter (Correct answer)
- An angle grinder
- A hacksaw
- A hydraulic spreader
Correct answer: A bolt cutter
Bolt cutters produce a clean, opposing shear cut on both sides of the shackle, leaving a distinctive flat, pinched cut pattern.
Question 5: The term 'key control' in a master key system refers to:
- The physical weight distribution of a key
- Restricting unauthorized key duplication through patented keyways and controlled distribution (Correct answer)
- Electronic logging of when keys are used
- The number of cuts allowed on a single key blade
Correct answer: Restricting unauthorized key duplication through patented keyways and controlled distribution
Key control systems use patented keyways, restricted blanks, and authorization protocols to prevent unauthorized key copying and maintain a documented chain of key issuance.
Question 6: Which lever tumbler lock component serves the same functional role as the driver pin in a pin tumbler lock?
- The curtain
- The post (gating post) (Correct answer)
- The bolt follower
- The keyhole escutcheon
Correct answer: The post (gating post)
In lever tumbler locks, the post (or stump) blocks lever movement unless the correct key lifts each lever to the exact height that aligns the gating slot with the post.
Question 7: A forensic examiner finds circular scratch patterns radiating from the keyhole on a deadbolt faceplate. This evidence pattern most strongly suggests:
- Repeated normal key insertion over time
- Drill attack targeting the pin stack
- An attempt to pick the lock with a rotary pick gun (Correct answer)
- Cylinder pulling with a slip ring
Correct answer: An attempt to pick the lock with a rotary pick gun
A rotary (electric) pick gun creates rapid circular motion that leaves distinctive radial scratch patterns around the keyway on the plug face and surrounding faceplate.
CFL Lock Identification & Key Systems 3
During a crime scene examination, a deadbolt cylinder shows a cracked plug and metal burrs on the plug face.
The most likely forced entry method is: