private detective

noun
1.
a detective who is not a member of an official force but is employed by private parties.
Also called private investigator.
Origin
1865-70
Examples from the web for private detective
  • Knowing this might require some professional help, she seeks out the jaded private detective who lives in her building.
  • The graphic novel is a good action-packed private detective story all on its own.
British Dictionary definitions for private detective

private detective

noun
1.
an individual privately employed to investigate a crime, keep watch on a suspected person, or make other inquiries Also called private investigator