Ariel Castro, the Cleveland man who kidnapped three young women and kept them captive in his basement for ten years, was found hanging in his cell at about 9:30 p.m. Tuesday night. He was transported to a hospital but was pronounced dead at 10:52 pm.

According to Ed Gallek, a reporter for Cleveland's Action 19 News, Castro was in protective custody and was supposed to be checked on every 30 minutes. His body was reportedly discovered during a regular security check.

In July, Castro, 52, pleaded guilty to hundreds of charges, including rape, kidnapping, and murder, and he was sentenced to life in prison, plus an additional 1000 years.

UPDATE 12:47 am: The Associated Press, citing an Ohio corrections official, is reporting that Castro's death was a suicide.

UPDATE 1:24 am: An Ohio corrections department spokeswoman told CNN that Castro's death is still under investigation.

"He was housed in protective custody which means he was in a cell by himself and rounds are required every 30 minutes at staggered intervals," JoEllen Smith of the corrections department told CNN in a statement.

"A thorough review of this incident is underway," she added.

[Image via AP]