Give a thief rope enough and he'll hang himself.

Meaning: A criminal given freedom eventually exposes himself through his own continued wrongdoing.

Origin: Usually said of any wrongdoer: given enough freedom, they will bring about their own downfall. The historian Thomas Fuller used an early form in The History of the Holy War (1639), and by John Ray's collection of 1678 it was proverbial. The image is the hangman's rope.