The Cleveland man who kidnapped three women and sexually assaulted them for nearly a decade in his basement was found dead in his jail cell Tuesday night after an apparent suicide.

A statement from the Ohio Department of Corrections said Ariel Castro, 53, was found hanging in his cell at the Correctional Reception Center in the town of Orient at 9:20 p.m. local time. After prison medical staff attempted to perform life-saving measures, Castro was transferred to The Ohio State University Wexner Medical Center in Columbus, where he was pronounced dead at 10:52 p.m.

Castro's death is being investigated by the Ohio State Police and the Department of Corrections. According to the statement from the latter, Castro was being kept in protective custody, isolated from other inmates due to his high profile, and was subject to checks every 30 minutes. He was in the cell by himself when he was found. Department spokeswoman JoEllen Smith told the Associated Press that Castro was not on suicide watch, which entails constant surveillance.

An Ohio coroner confirmed reports that Castro did indeed commit suicide by hanging himself, apparently with a bed sheet, Reuters reported.

Castro's attorneys tried unsuccessfully to have a psychological examination of Castro done at the Cuyahoga County Jail, where Castro was housed before he was turned over to state authorities following his conviction, his attorney, Jaye Schlachet, told The Associated Press early Wednesday. Schlachet said he could not immediately comment further.

Castro, a former school bus driver, was sentenced to life in prison plus 1,000 years on August 1 for kidnapping and sexually assaulting Amanda Berry, Michelle Knight, and Gina DeJesus while holding them captive in his house.

He even fathered a daughter with Berry, but was barred from seeing the child after a judge rejected his request for visitation rights as a consequence of his sentence. Investigators say the women were bound with chains, repeatedly raped and deprived of food and bathroom facilities. Knight told investigators she was beaten and starved several times to force her to miscarry.

In a rambling statement, he told the judge he was not a monster, but a man suffering from a pornography addiction, saying "I'm not a monster. I'm sick."

Knight was the only one of the three who appeared in court at his sentencing.

"You took 11 years of my life away, and I have got it back," she said in the hushed courtroom. "I spent 11 years in hell. Now your hell is just beginning."

The three women were kidnapped between 2002 and 2004. DeJesus was 14 at the time of her abduction, while Berry was 16 and Knight was 20 years old. They escaped May 6, when one of the women broke down part of a door and yelled to neighbors for help. Castro was arrested that evening.

In an interview last month after Castro's conviction, Schlachet and attorney Craig Weintraub said their client clearly fit the profile of sociopathic disorder and that they hoped researchers would study him for clues that could be used to stop other predators.

The Associated Press contributed to this report