The Friends of Eddie Coyle (1973)

Eddie's friends are numerous, but the term "friends" is suspect. As a small time hood, Eddie is about to go back to jail. In order to escape this fate, he deals information on stolen guns to the feds. Simultaneously he is supplying arms to his bank robbing/kidnapping hoodlum chums. But who else is dealing with the feds? Who gets the blame for snitching on the bank robbers?