According to the Burglary Prevention Council, about 60 percent of burglars gain entry by using force. Doorknobs can be vulnerable to a forced attack. While some signs of forced entry are immediately noticeable, such as when a door is kicked in, other signs involving doorknobs may not be noticed at first. If you see any signs of a break-in or forced entry, do not enter your house, instead, call the police.
Key Bumping Evidence
Key bumping is a technique using a similar key, made with a heavier metal than the pins, to essentially file down the pins on the inside of the lock. As noted on Flam's Lock & Key website, victims may have problems with their insurance claims in such a situation, because this technique may leave no sign of force on the outside of the lock; however, the Lockpicking Forensics website notes that some locks will show evidence of the top of the key impacting the lock.
Tool Mark Giveaways
Heavy scrapes or marks on your doorknob can be indicative that someone has gained entry to your home. According to the Lockpicking Forensics website, thieves use screwdrivers to forcefully break the pins in the lock. Deep scratches or even a widening of the keyhole are signs that someone may have used a screwdriver or other implement on your doorknob.
According to the Lockpicking Forensics website, drilling involves taking a drill to the lock and drilling out the pins, which allows the lock to turn freely. A drilled lock will be immediately noticeable because there will be a hole where the keyhole used to be.
Lockpicking is less forceful but still an invasive technique, which will leave signs on the doorknob, such as lighter scratches around the lock. According to the Lockpicking Forensics website, however, the real signs will be found on the inside of the lock on the pins. Depending on the skill and force used by the burglar, the pins will have dents and scratches from the pick.