Criminals are using phony warrants to rip off unsuspecting residents.
The Allegheny County Sheriff's Office says the scam artists identify themselves as deputies and ask people to pay a fine for failing to appear in federal court.
People are told they will be arrested if they don't pay the fine immediately.
The Sheriff's Office says warrants are never discussed on the phone, or by text or email.
Also, the only people who serve federal warrants are US Marshals.