While in prison he was the subject of much debate on the tendencies of criminals and their mental states. Gardner was studied by alienists and doctors alike. He was shipped to Atlanta and then Alcatraz, then back to Leavenworth where he was released in 1938. He tried to make a life for himself after prison.
All men who serve more than five years in prison are doomed, but they don’t realize it. They kid themselves into a belief that they can come back, but they can’t.
Those words were written in Gardner’s last note before he concocted a mixture of poison gas and killed himself in the bathroom of a San Francisco hotel.