He moved to Spain in 1973. On August 26, 1979, he died by what was originally ruled suicide by the authorities, as sleeping pills were found by his body, but later it was ruled death from natural causes. Some closer to the scene say foul play may have been involved. Robert Livesey, who co-wrote Karpis's 1979 book, said Karpis was not the type to commit suicide. Livesey said Karpis was a survivor, having served 33 years in prison, and also stated Karpis was anticipating the publication of the book. Livesey believed Karpis had been introduced to pills and alcohol by his last girlfriend Nancy, to give a relaxing high, and perhaps Karpis accidentally over-indulged on one occasion, with fatal consequences. No autopsy was performed, and Karpis was buried the next day in Spain.