The Beatles first came to the United States in February 1964 when Manson was an inmate in the United States Penitentiary at McNeil Island in Puget Sound. He was serving a sentence for attempting to cash a forged U.S. Treasury check; he was 29 years old. His fellow inmates found his interest in the Beatles "almost an obsession". Inmate Alvin Karpis taught him to play the steel guitar, and Manson told many people that "given the chance, he could be much bigger than the Beatles."