Transcript for Man Freed Decades Later, Still Denies Ariz. Double Murders
Well, today in arizona, a 77-year-old man took his first free breath in 38 years. Of course, people leave prison every day in this country, but what makes this moment extraordinary are the twists and turns that preceded it. The double homicide, the exwife's accusations, the desperate decades spent trying to prove innocence. Abc's dan harris has been following this story for years, and brings us the very latest in this "nightline" investigates. Reporter: You are looking at bill macumber's first breaths of freedom, after serving 38 years for a double murder he says he did not commit. Big day, family day. Reporter: This scene, the culmination of an astonishingly nasty fight between macumber and two powerful women. His ex-wife and also the governor of arizona. Late today, at his first news conference, macumber cried when talking about the lawyers who fought to get him out. Excuse me, excuse the emotion, but -- I'm here because of all these people. So -- I wouldn't be here without them. Reporter: In the 1970s, macumber was convicted of killing two young adults and leaving their bodies in the arizona desert. We first started covering this story in 2010, when we met bill ma come berp's son, ron, who had been raised to believe his dad was a monster. Not long before we met him, though, ron got a call from a lawyer with the arizona justice project, which works to free innocent inmates. He says, there's no other way to tell you think. We think your father's innocent and we're pretty sure your mom framed him for it. Reporter: At the time of the arrest, the marriage was falling apart. And carol was working at the local sheriff's office, where she had access to the evidence. I don't have any doubt anymore. That my mom did this. That my mom framed my dad. Reporter: Did you frame your husband? No. Absolutely not. Reporter: Back in 2010, we managed to track down ron's mother, carol kempfert, at her home in olympia, washington. I didn't just wake up one morning, saying I'll frame my husband today. I'll be happy to take a polygraph. I did not tamper with any evidence. Reporter: The notion that your son would say that you're capable of acting in such a diabolical fashion is -- it's a damning statement. Ron -- boy, I don't know if i want to get into this. Ron always has been a follower. Reporter: You think he's gullible? Critical thinking is not one of ron's better skills. What can I say? And if anyone was ever made for bill to mold and manipulate, it would be ron. Let's say my father is manipulating me. Explain to me how he's been manipulating the arizona justice project and everybody that believes in his innocence and is fighting to get him out. Reporter: There was another group that believed bill ma come berp's story. The arizona clemency board, which, in a rare move, unanimously recommended his sentence be commuted, saying, an injustice has been done. The board pointed out that another man, ernesto valuen sway la con veszed to the murders. Even though governor jan brewer had hand picked the members of the clemency board, she rejected their recommeion and refused to speak about it with us or the family. Governor, my name is dan harris, I'm from abc news. So, ron and I showed up at one of her press conferences. Why won't you release him? Well, you know, it's an unfortunate situation that governors have to make difficult decisions regardless of what recommendations are made to them. I appreciate your concern but I've made my decision and it's final. All right, guys -- Reporter: Executive clemency board, this is your board. Why wouldn't you follow the recommendation of your own board, governor? Is there political motive here on your port? Desire not to look soft on crime, per se? Absolutely not. Reporter: But then macumber's lawyers launched a last ditch effort to clear his name in court. An effort so strong that prosecutors finally agreed to offer macumber a plea deal and the judge set him free. Mr. Macumber, good luck to you, sir. Thank you, your honor. Reporter: At his new conference today, macumber marvelled at how the outside world had so utterly changed and talked about his first hours of freedom. I allowed myself one beer. After 38 years. I was a little bit hesitant to go beyond that point. We just hugged each other. There was nothing to be said. This is what we've been -- i can't say it enough, this is what we've been waiting for. Reporter: Macumber was asked about governor brewer. Can't say something nice about somebody, don't say nothing at all. So, with your permission, I'll say nothing at all. Reporter: We tried to get a comment from the governor, but her spokesman did not respond. We did speak with carol kempfert. My first reaction was -- i just -- I didn't believe it. Reporter: Who requested we con zeile her face because she recently had a stroke that left her partially paralyzed. I can't convince people that -- that I didn't frame 4i78. They are going to believe whatever it is they're going to believe. But I'm here to tell you, they just let a double murderer out. Reporter: Today, macumber said both of those things are untrue. I never hear her name again, that's fine. Reporter: At 77 and in failing health, it is unclear how much time he has left. But today, at least, it did not seem like bill macumber would spend his newfound freedom wallowing in bitterness. Justice, however late, is still justice. Reporter: For "nightline," this is dan harris in new york.
This transcript has been automatically generated and may not be 100% accurate.