Transcript for Michigan Valedictorian Matricide Trial: The Prosecutors' Case
I am. We have to switch gears right now. We have to go to the michigan high school valedictorian that is facing charges for murdering his mother. First, here's abc's john muller. Reporter: It's hard to imagine that this jeffrey pyne is the same jeffrey pyne is the same valedictorian and a university of michigan biology student. But today, ten women and four men will hear opening statements in pyne's first-degree murder trial. The 22-year-old accused of killing his own mother. In 2011, ruth pyne's body was found bludgeoned and stabbed 16 times in their home. The prosecutors focused on jeffrey. Reporter: After five months of an investigation, jeffrey was charged in october 2011 of beating her to death and locked up without bond. Pyne's father told abc news, he believes he is innocent. A sentiment shared in the community. It took a judge 2 days to final 14 impartial jurors. The people in the community are hugely supportive of this young man. Even people who believe he may have killed his mother. I absolutely don't believe that jeffrey pyne is guilty of this murder. He loved his mother very much. Reporter: But court records show ruth had a history of mental illness for 14 years. And nine months before her death, she was accused of trying to strangle jeffrey and spent two weeks in jail. We did know she was ill. But the family never let on the nature of the illness. Reporter: Indicted by a secret grand jury, little is known about the evidence against him. This was a rage killing. That certainly lines up with the prosecutor's intention that this was an angry, young man who had had it with his mother. Reporter: Jeffrey pyne maintains his innocence. But if convicted, he faces the possibility of life in prison without parole. Let's get to our legal team. Nancy grace. And our "gma" legal correspondent, dan abrams. Welcome to you both. Nancy, you're a former federal prosecutor. Do you see evidence here for a first-degree murder conviction? As of right now, absolutely not. I don't see it. But we all keep saying they're going to show us more in opening statements, which are slated to begin at 8:30 this morning. Within about an hour, we'll hear all the state's got in their opening statement. As dan would agree, we hope there's going to be more evidence and there's not. We know it all. This is what is concerned me. Jury nullification. You saw it in o.J. Simpson. You saw it in lorena bobet. They like the defendant. I think this is rife for jury nullification. Anytime a prosecutor in america hears nancy grace say their case is weak, they're in trouble. I didn't say that. I said we haven't heard the evidence yet. I like this guy, dan. When I found out, now that have a child. Yeah? If somebody were beating your child, the mom started beating this boy, now a man, when he was 9 years old, and beating the little girl. She tried to strangle her son. The jury may say, she got the death penalty. You're saying she deserves to die because the defense here isn't that it was self-defense. The defense is that he wasn't there, nancy. The defense is, keeps saying, i wasn't there. If his claim was self-defense, i totally agree with you. But when he's saying I wasn't there, he's putting it all on the table challenge the prosecution's case. Dan, let me school you again. Please, do. That's not what jury nullification is about. Right. Jury nullification is when they hear the evidence. Take a look at this jury. You have a working-class, highly-educated jury. They're going to understand the evidence. In jury nullification, even if the evidence is strong. I don't think they need to nullify. They don't need to nullify here. Never -- right. Right. This is what I know. I want to press one point. They don't need to nullify, though. The bottom line is, if the -- they don't have more evidence than the prosecution has already laid out. And part of the prosecution's case is going to be that the motive was the mother's mental illness, the mother beaten him in the past. Here's what I want to get to, nancy. No. Let me bring this to you. Not surviving the legal verdict. If the prosecution does come up with evidence that proves that jeffrey was at the scene. We know he had bloody hands and other circumstantial evidence. If they can prove he was at the scene, does that change your view? Frankly, I may end up going along with the jury because even though they may prove a murder. They have his cell phone placing him at the area. They have wounds on his he was a handy man, in addition to going to college a a biology major. So, he can explain those wounds away that way. But he lied to police about where he was that day. He said he was transplanting lilac bushes for a lady that he worked for. He said, no. It wasn't that day. It was another day. Is that enough to prove murder? Even so, you put a hand on my son or my daughter, you might get the death penalty. You understand what I'm saying? And a jury may agree with me. The bottom line is, it may seem like nancy and I are disagreeing. But we actually agree on the fundamentals. It's a tough case. Impossible. Tough case to win, based on the evidence that we've seen already. And I think that they're going to have to present more because you both got the sympathy and the lack of evidence together. Dan abrams, nancy grace, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.