He served only weeks for a life sentence plus 1000 years for the kidnapping of three women who he held in his Cleveland home.
Castro was found dead in his cell in the Ohio prison where he was supposed to have been checked upon every 30 minutes.
The sociopath who plead guilty to a total of 977 charges which included the murder of an unborn child and the rape of his captives held the world in awe at the scope of his criminality and depravity.
He was caught after Amanda Berry, 27, escaped together with her six year old daughter.
According to the Ohio Department of Corrections, Castro was found hanging in his prison cell at the Correctional Reception Center in Orient, Ohio, around 9:20 p.m. Tuesday. Although prison medical staff attempted to save him he was later pronounced dead at the Ohio State University Wexner Medical Center.