Michael Robinson, 32. Photo courtesy of the Dallas County jail

A man is charged with capital murder after he admitted to sexually assaulting and killing his 71-year-old grandmother with a fire extinguisher Friday in her Old East Dallas home, authorities said.

Police found the victim, Irish Harrison, at 10:30 a.m. Saturday while responding to a welfare check at her home in the 4900 block of Terry Street.

Her grandson, 32-year-old Michael Robinson, was sitting in the living room with blood on his clothes when officers arrived, according to an arrest affidavit. He told police that while he was there, he made sexual advances toward Harrison. She tried to get away, but Robinson forced her to the ground and sexually assaulted her, according to the affidavit.

He then hit her several times on the head with a fire extinguisher, according to the affidavit.

Robinson was taken to the Dallas County jail, where he remained Monday in lieu of $1 million bond.

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