Who are detectives and what is their job?

A detective is a police officer with a promotion (you aren't required to be a police officer before you become detective, but most detectives DO start out as police officers).

Regular police officers patrol a certain area or areas, while detectives investigate specific cases. Regular police officers are sort of like security guards for a neighborhood, patrolling for crimes in progress and warning or arresting the offenders, while detectives are assigned to investigate a crime that has already happened.

Like, if a couple of beat cops notice a homeless man robbing a stabbed and bloody corpse, they would stop the guy and arrest him. Then it would be the detectives' job to figure out what happened. If it turns out that the homeless man didn't kill him, and was just taking advantage of the situation by robbing the man (corpses make very easy targets for robbery), then it would be the detectives' job to figure out who really killed him.

New police officers often hope to "make detective" one day, while others prefer to remain working as "beat cops."

See the Related Links for more information about a police officer's job versus a detective's job.