stool pigeon

"Neither am I asking you to be a stool pigeon," said the detective.

If I were to guess at it I should say he was a detective's stool pigeon.

Was Reese merely a "stool pigeon" or was he an "agent provocateur?"

Of course, it was possible that Kurt was a stool pigeon, leading him on as a test.

"Which one of you is the stool pigeon," came the harsh query.

When the stool pigeon once more stood in the doorway, rattling his half dollars, they followed him into the den of the tiger.

"Some doity li'l' stool pigeon," added another, who was more doubtful still.

I've been expecting just this thing ever since you began playing the game with Conway there as a stool pigeon.

Of course, in a case of this sort, "stool pigeon" men are useless, for no professional crooks are involved.

“I detest a stool pigeon,” said Mr. Gandiss after Joe the Sweeper had slouched away.