Transcript for Valedictorian Murder Trial Verdict: Jeffrey Pyne Guilty
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.