CHAPEL HILL, N.C. (WTVD) -- A Chapel Hill man died of natural causes after apparently stabbing his mother 74 times in their Chapel Hill home back in 2017, according to the newly released autopsy.The two were found dead by a realtor in their home on Deming Road on Oct. 12, 2017.At the time, police said they believed 86-year-old Margaret Montgomery Gibson was killed by her son, 58-year-old Eric Dana Gibson.According to the autopsy, Eric was found with a knife "clenched in his hand" and he was "in a prone position overlying his mother" in the bathroom.Two additional knives were found nearby.The autopsy determined that Eric died from "hypertensive and atherosclerotic cardiovascular disease" with obesity listed as a contributing factor. His manner of death was ruled natural.According to the autopsy, Eric had a history of schizophrenia.Margaret's autopsy showed that she had at least 74 sharp force injuries to the head, neck, torso and left hand. Her manner of death was ruled a homicide.According to the autopsy report, Eric was unhappy that his mother planned to move both of them to California.