The Getaway (1941)

A government agent goes under cover in prison to gain confidence with a wanted criminal and get information regarding his gang. The two make an eacape and the agent pretends to be a loyal confidant aiding the criminal in recuperating after he is shot in the escape. In the midst of this, the agent meets the criminal's sister, who is looking to just visit her brother, viewing him through rose colored glasses as just a small time crook she can reform and not the dangerous murderer he is in reality. The agent falls for the sister and this adds additional difficulty to his mission.