Further tests are to be carried out on the body of a 97-year-old woman who died three years after being badly beaten in her home, police say.
Ada Hopkinson confronted Brough in her hallway
Ada Hopkinson died on Sunday in hospital in Cheadle, Staffordshire, after never regaining consciousness following the assault in March 2005.
Benjamin Brough, 20, was cleared of attempted murder but convicted of wounding and jailed for 12 years.
Police are liaising with the Crown Prosecution Service, a spokesman said.
During his trial, the court heard that Brough, who was 17 at the time of the attack, had broken in to burgle Mrs Hopkinson's end-terraced house in Shirburn Road, Leek.
He was confronted by her in her hallway where she was attacked and left with severe facial and head injuries. Brough fled empty-handed.