From the Cary Grant film (1955) and the Robert Wagner TV series (1968), the theme is "it takes a thief to catch a thief".The original proverb is "set a thief to catch a thief".
Ahhaaa :) That's a pretty good question, actually.Weell, i gueess, of course... all thiefs are friends. :P But what will really happen is, they'll saayaa.. gaassshhh, why the helldid you steal maa...