Ariel Castro was being held in protective custody in isolation from other inmates at the Correctional Reception Center in Orient, Ohio when he was found dead last night.
According to media reports in the US, he was being checked on every 30 minutes.
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Rain will spread southeastwards through N. Ireland, Wales and England overnight.
The woman used her daughter's own Facebook page to live-stream the attack after the teenager posted provocative pictures online.
A senior employee at the organisation reportedly derided the three-year-old royal for being 'royal, rich' and "advantaged'.