WMG / Beat the Devil

Julius O'Hara is Dr. Einstein from Arsenic and Old Lace.

Both are Germans using obviously fake names. Both are reluctant crooks on the run. Enough time has passed to explain the doctor's changes in personality, died hair, and obvious aging. He's gained more social confidence since escaping Johnny all those years ago, but has also become more cynical and world-weary. At the end of Beat the Devil he seems more irritated about being arrested than anything else, because he's done this a million times before.