The accomplices of thieves are their own enemies; they are put under oath and dare not testify. (NIV)
Whoever is partner with a thief hates his own life; he falls under the curse [pronounced upon him who knows who the thief is] but discloses nothing. (AMP)
Whoso is partner with a thief hateth his own soul: he heareth cursing, and bewrayeth it not. (KJV)