an inside job
set phrase A crime committed by someone who is closely involved with the targeted person or group. The robbery must have been an inside job—only three people have access to the safe.
inside job
a crime committed by someone working or living at the scene of the crime. There was little doubt that it was an inside job, thought the inspector. It's a particularly cunning way to carry out an inside job.
an inside job
n. a crime perpetrated against an establishment by someone associated with the victimized establishment. (Underworld.) It was an inside job all right. The butler did it.