(13WHAM) Rochester N.Y.- A Henrietta man whose guilty plea in his father's fatal stabbing was later thrown out has pleaded not guilty by reason of mental disease or defect.

Michael Mox was accused of killing 81 year-old Stephen Mox at the family home in July 2007.

According to 13 WHAM, his lawyer William Easton noted in court Tuesday that Mox was diagnosed as a paranoid schizophrenic at the age of 19 and spent many years in and out of institutional care. Mox was released from a facility less than three weeks before his father's death. The plea allows for an additional mental health evaluation after which, Mox could be committed to a mental health facility for the rest of his life or unless his mental health status changes significantly.