DAVID KLEINFELD IN CARLITO’S WAY (1993)
Criminal client and pal Carlito Brigante (Al Pacino). A lawyer who gets too involved in the criminal world that provides him his clients, Kleinfeld (Sean Penn), who is the object of a federal investigation, decides to sell out his old friend by making false accusations about the retired gangster.
Punishment for snitching:
Rather than simply kill his double-crossing lawyer, Carlito secretly empties his revolver, leaving Kleinfeld defenseless when the son of a mafia boss he's stolen from and killed comes to whack him. It's much easier to sleep at night that way.