Correctional Reception Center prison officials in Orient, Ohio suspect that convicted kidnapper Ariel Castro has committed suicide because guards found him hanged in his cell during a routine 30-minute check on Tuesday, September 3.

Castro was under protective custody while at the prison. He was isolated from the other prisoners for his own protection. Guards check on prisoners in protective custody once every 30 minutes.

He was under suicide watch while at the Cuyahoga County Jail. Guards at the jail checked on him every ten minutes. However, he was not on suicide watch at the prison, the Associated Press reports.

Medical staff at the prison tried to revive Castro, but they were not successful. Castro was taken to Ohio State University Medical Center, where he later died, MSN News reports.

"A thorough review of this incident is under way and more information can be provided as it becomes available pending the status of the investigation," Rehabilitation and Correction Department spokeswoman JoEllen Smith told The Chicago Tribune .

Jaye Schlachet, one of Castro’s attorneys, wanted Castro to have a psychological evaluation while he was still at the Cuyahoga County Jail. That evaluation did not happen for reasons that are unknown at this time.

The house where Castro held three women captive for years has been torn down.