Transcript for Michigan Valedictorian Accused of Killing Mother
First, let's turn to the high school valedictorian in michigan who is now on trial for allegedly murdering his own mother. Family and friends, including his own father, are coming to his defense right now. And abc's john muller joins us with the latest on this. Reporter: Good morning. The idyllic son accused of killing his mother. The son says he didn't do it. An entire community has rallied around him. He was by all accounts the perfect son. A university of michigan biology student. He was the high school valedictorian and star athlete. But later today, the 22-year-old goes on trial, accused of viciously murdering his own mother. Ruth pyne's body was found bludgeoned and stabbed repeatedly in their home in may of 2011. The whole thing, you know, really upset the entire neighborhood. Reporter: After five months of investigating, her son, jeffrey, was indic charged with beating her to death and put in jail. I really don't think jeffrey did it. He was no threat for five months. Why was he all of a sudden a threat? Reporter: Ruth's husband, pyne's father, says he believes his son is innocent. But by all accounts, what happened in this suburban home is a complicated story. Court records show ruth had a history of mental illness and was allegedly often violent. In 2010, she was accused of attacking jeffrey, allegedly beating him and attempting to strangle him. She was jailed for two weeks. Her own psychologist recommended she became impatient. Did the violence history with the mother provide a motive for the son to commit the murder? Reporter: Little is known about the evidence against jeffrey pyne. Prosecutors point to wounds on his hands after the killing. Jeffrey said he was at work at the time of the murder and maintains he's innocent. And this morning, as his trial begins, his neighbors and former teachers and much of the community where he grew up agree. We don't feel that the real murderer has been caught. We feel there's someone out here that did it, other than jeffrey. Reporter: In fact, the defense for jeffrey pyne is expected to say just that. That the wrong guy is locked up while the real murderer is out there. Despite the family history, the defense is not expected to claim he snapped or acted in self-defense. They say he's innocent. For more, let's bring in "gma" legal analyst, dan abrams.
This transcript has been automatically generated and may not be 100% accurate.