ELI5: how would they know which side of a door it was locked from?

r/

A documentary I am watching just said “detectives discovered the door was locked from the outside.” How would they be able to determine which side of the door it was locked from, assuming it’s a standard front door?

Comments

  1. Doctor_Expendable Avatar

    It has a lock on the outside that can’t be unlocked from the inside. 

    When you leave your house your door locks from the inside. Meaning you don’t need a key to open it from inside.