A former valedictorian and college biology student is accused of stabbing his mother 16 times and beating her over the head with a 2x4 inside the family’s Michigan garage.  Prosecutors say 22-year-old Jeffrey Pyne was angry with his mother, Ruth, when he viciously attacked her.

Ruth had a history of mental illness. She was reportedly bi-polar and spent years in and out of hospitals. Court documents say she even spent two weeks in jail after trying to strangle her son.

Jeffrey Pyne says he is innocent, and he wasn't even at home when the attack happened.

For more on this story, watch Jane Velez-Mitchell weeknights at 7 p.m. ET on HLN.