Transcript for Martin MacNeill Jurors Hear Testimony on Jailhouse Conversations
We begin with the latest on the dramatic trial of the utah doctor accused of killing his wife. The prosecution is expected to rest today after several inmates testified about their jailhouse conversations with the defendant. Abc's aditi roy has all the latest on that. Aditi, good morning. Reporter: Good morning, lara. As the prosecution wraps up its CASE, THREE OF martin MacNeill's fellow inmates took the stand. Their identities withheld for security reasons. They testified that the former utah physician made unflattering comments about his wife. We're going to refer to you as inmate number three. Is that okay? Yes, sir. Reporter: Introduced to the court as inmates two, three and four, three men who spent time behind bars with martin MacNEILL, TOOK THE STAND Tuesday. Their identities masked from cameras. Did you become friendly? Yes, sir. How did that happen? I worked out a lot. And he asked me questions about working out. Sooner or later, we start working out together. Did he have a nickname? Doc. Reporter: The former physician was behind bars from 2009 to 2012, for an unrelated identity fraud case. MacNEILL IS NOW ON TRIAL FOR Allegedly murdering his wife, michele. PROSECUTORS say MacNeill killed his wife in order to continue an affair. MacNEILL MAINTAINS HE IS Innocent. But one of his former inmates SAY HE approached MacNeill, after finding a magazine article about his wife in the prison library. I said, doc, they say you murdered your wife. He was like, I didn't murder my wife. If I did, they don't have any evidence. He just mentioned that they couldn't prove it. That medication she was taking, given him, prescribed. Did he say whether he did or didn't kill her? He just said, they can't prove it was me. Reporter: All of tin mates said MacNeill told them he didn't kill his wife, two said he used derogatory words to describe her. He said, if they could prove that, you think I would be sitting here talking with you? So, I said, what did you do? He said, . He referred to her as a ? Yes, sir. Okay. Reporter: The jury is expected to hear from one more fellow inmate today. And prosecutors will wrap up their case today or tomorrow. And that's when the defense begins its case. George? Aditi, thanks. Let's talk about this now, with dan abrams. The prosecutors putting out such a powerful case. These are icing on the case. The witnesses here. The defense is going to say, wait a second. Every, single time he says he didn't do it. But I think that enhances the credibility of these witnesses. Imagine if they had all come in and every single one said, he confessed. And the defense would be saying, come on. You're doing this to get better treatment, et cetera. Here, you have them saying he didn't confess. But he was basically trashing his wife. I think that adds to the power of these witnesses' testimony. And it sounds so real, when they have him saying, they can't prove it. The best hope for the defense at this point, wrapping up the prosecution's case, I think the best hope for the defense, is these jurors get back there and talk about it. And say, I think he wanted to do it. I think he was planning on doing it. But I'm not convinced beyond a reasonable doubt that he actually went ahead and did it. Now, I think that's a long shot at this point. This is a strong prosecution case. But that's the best hope. That the jurors think when it comes to did she actually die at his hands? I'm not sure it's been proven beyond a reasonable doubt. Beyond a reasonable doubt is always such a high bar.
This transcript has been automatically generated and may not be 100% accurate.