The sordid tale of Cleveland kidnapper and rapist Ariel Castro has taken another lurid turn, with officials saying his death may have been caused by auto-erotic asphyxiation.
Castro, 53, died in September - a month after he was sentenced to life in prison plus 1000 years, for holding three women captive and treating them like sex slaves for a decade.
It was an abrupt ending to a sordid case that shocked the world with revelations of depravity and brutality carried out in an ordinary Cleveland home.
Details of his death, previously thought to be suicide, were released in a report with the results of an Ohio state prison internal investigation.
Castro was found hanging from a hinge in the window of his cell by a sheet wrapped around his neck with his pants and underwear pulled down to his ankles.
"The relevance of this finding is unclear," the report concluded, adding that the details were "relayed to the Ohio State Highway Patrol for consideration of the possibility of auto-erotic asphyxiation."
Castro had left no note and given no indication of suicidal tendencies, the report noted, adding that "no other immediate observations about the scene led to conclusions about the motivation for the self-inflicted death."
The investigation also found that prison guards failed to check on Castro every 30 minutes - as required by his special circumstances - and falsified their logs.
However, video surveillance cameras showed that guards performed the required check at 8.45pm and again at 9.15pm, when he was found hanged in his cell.
Castro's crimes - committed when he imprisoned the women in a so-called 'house of horrors' - led to an outpouring of national pity for the three victims, Amanda Berry, now 27; Gina DeJesus, 23; and Michelle Knight, 32.
They were abducted separately between 2002 and 2004 at the ages of 14, 16, and 20 and held captive in a working class neighbourhood of Cleveland.
They escaped on May 6 when Berry managed to break open part of the front door and call out to a neighbour for help. She emerged from the dilapidated house with a young daughter who was fathered by Castro during her captivity.
Castro pleaded guilty on August 1 after prosecutors agreed not to seek the death penalty and the house was demolished a few days after he was sentenced.
