officer

patrolman, policewoman

detective, inspector, investigator, plainclothesman, sherlock, sleuth

marshal (also marshall), sheriff, trooper

peace officer

captain, lieutenant, sergeant

constabulary, heat [slang], police, police force

operative, private detective, private eye, private investigator

bureaucrat

administrator, commissioner, director, executive, head, manager, regulator, superintendent, supervisor

chair, chairman

flunky (also flunkey), minion, underling

co-official