GIBSONIA — The family of a Western Pennsylvania man who’s accused of stabbing his elderly grandmother to death during breakfast says they’re speaking out about his mental illness.

Levi Daniel Staver, 26, struggled with Asperger’s syndrome and schizophrenia.

Ruth Johnson said Tuesday that Staver believed his grandmother had tried to attack him, though that never happened. He’s been charged with criminal homicide in the Feb. 19 death of 76-year-old Constance Johnston.

Police say Staver came upstairs from the basement and stabbed Johnson in the back with a hunting knife.