We want to get right to the verdict for the former michigan valedictorian, jeffrey pyne, convicted of second-degree murder. And abc's john muller has the story. We, the jury, find the defendant guilty... See More
We want to get right to the verdict for the former michigan valedictorian, jeffrey pyne, convicted of second-degree murder. And abc's john muller has the story. We, the jury, find the defendant guilty of second-degree murder. Reporter: At first, 22-year-old jeffrey pyne looks stunned. Is that your verdict? Reporter: As each juror confirmed the verdict. Yes, your honor. Reporter: He began shaking his head. Yes, your honor. Reporter: Once a high school valedictorian, pyne is now convicted of second-degree murder for the brutal bludgeoning of his mother, ruth pyne, in 2011. Outside the court, his father remains supportive but grief-stricken. I wasn't there to protect my wife when I needed to be. And I wasn't able to get him home for his sister for christmas. It's not been a good year. Reporter: The evidence was mostly circumstantial but troubling. He never asked what happened. Reporter: Jurors didn't believe massive blisters on pyne's hand came from an injury on the job, as he claimed. Can you verify you left at 1:30. Reporter: They did buy the prosecution's motive, that jeffrey pyne killed his mother after years of pent-up rage. Many refused to believe the star athlete and student was a murderer. But experts told juror, the extreme violence was consistent with a killer deeply connected with his victim. The defense never called a witness. Pyne never took the stand. After the verdict, his lawyers sat stunned. I could have been knocked off with that verdict. Reporter: Speaking on ruth pyne's behalf, her surviving sister. This is a heinous crime. Ruth pyne was a victim. Reporter: Now, it's up to the judge. If he's lenient, jeffrey pyne could get 8 to 12 years. If he's not, he could get life behind bars. For "good morning america," john muller, abc news, new york.
This transcript has been automatically generated and may not be 100% accurate.