Gang Busters (1955) on Netflix

Plot summary

The man Walsh picks up has his arm in a sling, and his manner makes the detective suspicious. A search of his car turns up a gun hidden in the sling, other weapons and a stolen vehicle, and the prisoner refuses to give his name. The police identify him as John Omar Pinson, whom the FBI lists as Public Enemy No. 4 for a string of robberies, and he is sentenced to life at the Oregon State Penitentiary. Inside, Pinson leads a group of inmates that includes Louie Feth, Mike Denike and Slug Bennett, and he coldly refuses the friendship offered by Wayne Long, a young criminal who is convinced Pinson is a mastermind.