Detectives

A detective is a secret police agent who wears street clothes and carries a concealed pistol and badge..

One of its functions is to discover who is the author of a crime. For it, sometimes you have to follow suspicious people, interrogate and look for clues.

The detective in this illustration has to stay in one place for a long time, because he's guarding a door across the street. to go unnoticed, he must pretend that he is engaged in some activity. Can you guess who it is?