Hayes was imprisoned at Sağmalcılar Prison in Istanbul. Following an incident in prison, he was transferred in 1972 to Bakırköy Psychiatric Hospital, described as a 'lunatic asylum'. On several occasions, the United States Department of State pressured Turkey to transfer sentencing to the United States; however, Turkish foreign minister Melih Esenbel stated that the US was not in a position to dispute a sentence issued by a Turkish court. He stated privately to officials that a release might be possible on humanitarian grounds, if Hayes' physical or mental health was deteriorating, but in a private consultation, Hayes stated to US diplomats that his experience at Bakırköy was highly traumatic, and he did not have confidence that the hospital would certify him for early release; Hayes also stated that he felt attempts to win early release would jeopardize his prospects of being transferred to a more desirable half-open prison. On May 12, 1975, the Turkish Constitutional Court declared amnesty for all drug offenses, which shortened Hayes' sentence from life to 30 years; he was transferred to İmralı Prison on July 11, 1975.