Ariel Castro, the Cleveland man sentenced to life in prison for holding three women captive in his home for a decade, was found dead in his prison cell on Tuesday night after apparently committing suicide by hanging himself, according to ABC News. 

The 53-year-old's body was found hanging in his cell around 9:20 p.m. at the Correctional Reception Center in Orient, Ohio, JoEllen Smith, Department of Rehabilitation and Correction spokeswoman, said early Wednesday in an emailed statement.

Prison staff members performed CPR, before Castro was later declared dead at the Ohio State University Wexner Medical Center, officials said.

According to the New York Times, Castro remained under protective custody because of the notoriety of his case. He was reportedly kept in a cell by himself and checked on every 30 minutes. 

Castro was not under suicide watch, according to Smith. 

Earlier this year, neighbors discovered three women in Castro's Cleveland home after hearing screams as one of them tried to break through the front door. The three women, Amanda Berry, 27, Gina DeJesus, 23, and Michelle Knight, 32, disappeared separately between 2002 and 2004, when they were 14, 16 and 20 years old, respectively.

They escaped on May 6, after Berry, broke part of a door and yelled to neighbors for help.

"Help me," she said in a 911 call. "I've been kidnapped, and I've been missing for 10 years and I'm, I'm here, I'm free now."

According to ABC News, the other two women were so scared of Castro that they held back initially even as police officers began to swarm the house. But quickly they realized they were free.

Castro, who was arrested the evening of their escape, later pleaded guilty to 937 counts including rape and kidnapping. 

All three were sexually abused and kept in confined torture chamber. According to the Times, the women were confined to two rooms on the second floor. The women were reportedly fed one meal a day and forced them to use plastic toilets in their rooms, the authorities said. 

Castro fathered at least one child with his victims, a six-year-old girl, born to victim Berry. 

After being sentenced on Aug. 1, Castro denied he had been violent or had sexually abused the women, saying whatever sexually action occurred were consensual. Castro denied being violent and claimed he was the victim of sexual abuse as a child and had become addicted to pornography.

According to ABC News, Castro attorney, Jaye Schlachet, said his client fit the profile of sociopathic disorder and hoped researchers would study him for clues that could be used to stop other predators.

Castro's attorneys tried unsuccessfully to have a psychological examination of Castro done at the Cuyahoga County Jail.

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."

It was not immediately clear how Castro was able to hang himself. The Ohio Department of Corrections statement said a review of the incident was under way.