My wife was stopped by a plainclothes state trooper in a black u

Cape May - My wife was stopped by a plainclothes state trooper in a black unmarked car with blue lights and all tinted out. He identified himself as lieutenant and showed a gold shield. This happened on the parkway just passed exit 6 south in a very secluded area. My wife said she did nothing wrong and he said just stopped you to check out your credentials. My wife seems to think he was not a trooper. Got nowhere trying to call state police have to call 9-1-1