Along with Freddie Barker, who he met in prison, Karpis led the Barker-Karpis gang on a five-year crime spree throughout the Midwest. The men stole over $1 million and killed approximately 10 people. On May 1, 1936, Karpis was captured in New Orleans by J. Edgar Hoover himself. (Karpis later said that special agents held him at gunpoint so Hoover could make the arrest.) He spent most of his 33 years in prison on Alcatraz, and was deported to Canada on his release, where he wrote his memoirs. He died in Spain from an overdose of sleeping pills.