Last seen in Lakeland: Is a husband responsible for his wife’s murder or is he imprisoned for the crime of another man?

Leo Schofield has been sitting in a prison cell for over 30 years, convicted in 1989 of killing his first wife Michelle two years earlier, and is still fighting to prove his innocence.

"Innocent is no part in it, no plan in it, didn't know it was happening, didn't know it was going to happen, and didn't want it to happen. That is me," he told "20/20" in an exclusive interview from prison that airs Friday, Sept. 23 at 9 p.m. ET.

Prosecutors argued that Leo Schofield, then 21, was a man filled with anger and waiting to explode against his wife.

Schofield’s defense attorney argued that there was no physical evidence connecting him to the stabbing homicide, and that the state’s timeline of events did not make sense.

Schofield's second wife Crissie and the non-profit organization The Innocence Project of Florida are among the supporters who have believed Schofield's story and have worked to exonerate him.

Evidence discovered in the past decade that Schofield and his supporters say link the murder to another man has become central to Schofield's case, but even that avenue has hit several legal roadblocks.

Michelle Saum Schofield, then 18, didn't arrive to pick up Leo from her job at a restaurant in Lakeland, Florida, on Feb. 24, 1987. Leo Schofield said he became concerned and began driving around town with his father and mother and talking to friends and family to find his wife.

Police, friends and family searched throughout the area and eventually found her car abandoned and broken into. Three days after she went missing, Michelle's body was found in a canal in Bone Valley, a region in central Florida.

She had been stabbed 26 times.

"I was so angry at God at that moment. I ripped my shirt off. I punched a tree, punched the ground, I was pulling grass out of the ground," Leo Schofield said.

Leo Schofield's past bouts of anger would become a factor in the investigation as neighbors, friends and family told investigators that he was volatile and argued with Michelle in their home. Multiple witnesses also described incidents of physical abuse by Leo against Michelle, including one account by Michelle’s best friend that Leo threatened to kill his wife.

A critical part of their investigation was an interview with a neighbor, Alice Scott, who told police that she heard the couple fighting from her bathroom the night Michelle Schofield went missing and that claimed she later witnessed Leo Schofield put a large object into the trunk of the car and drive off.

A couple who lived near the Schofield's told police that on the morning after Michelle Schofield's disappearance they saw her car and a truck belonging to Leo Scofield's father near the location where her body was found.

Police arrested Leo Schofield in June 1988.

Schofield's attorney questioned Scott's testimony at trial, claiming the timing of the alleged fight in the home conflicted with accounts of where he was seen at the time. Schofield's attorney said that Scott's testimony claimed the argument took place shortly before Leo Schofield was with his wife's father, which was several miles away.

The attorney contended that he couldn't have traveled from their home to his father in law's residence that quickly.

“In any case that you've looked at, you're going to find some discrepancies with witness testimony,” former Polk County State Attorney Jerry Hill, who presided over the Schofield criminal investigation, told 20/20, “It's human. I don't think any witness was looking at their watch saying, ‘There's Leo.’ I think they were being as honest as they could be in approximating exactly what they observed.”

Alice Scott could not be reached by ABC News for comment.

During the trial, prosecutors called in 21 character witnesses who testified about accounts where they saw Leo Schofield act aggressively and violently. Some described events where they say Leo Schofield was physically abusive towards his wife including pulling her hair.

On the stand Schofield denied claims made by witnesses but admitted to slapping his wife twice.

Schofield maintained to 20/20 that he never physically hurt his wife during their relationship.

"Physical abuse is one type of abuse and then you have the emotional abuse, which I'm guilty of," he said. "I did a lotta yelling…and I wasn't beyond punching a wall and being very theatrical," he said.

In the end, a jury convicted Schofield of first-degree murder and he was sentenced to life in prison.

Schofield continued to maintain that he was not involved in his wife's murder for years, and things began to change after he met Crissie Carter, a former state probation officer who later became a therapist and taught at Schofield's prison, in 1991.

After listening to Schofield's story and reviewing the court records on this case, Carter told "20/20" that she, too, believed he was innocent based on what she said were holes in the prosecution's case.

"What the state said is not lining up and what he's saying lines up exactly," Crissie Carter Schofield told "20/20."

Their relationship would soon become personal and the pair eventually married and adopted a baby.

During her research, Crissie says she came to a major discovery: fingerprints that investigators had found inside Michelle's car had never been identified.

"Whoever's fingerprints are in that car had to know something. We've got to figure out who that person is," she said.

Crissie Schofield hired a new defense attorney, Scott Cupp, who was able to obtain a copy of the fingerprints from the Florida State Police in 2004.

The prints were later run through the Automated Fingerprint Identification System, which was not available to Polk County investigators at the time and matched those of convicted murderer Jeremy Scott, who was serving a life sentence for a 1988 homicide.

Jeremy Scott is not related to Alice Scott, the neighbor who testified against Leo Schofield.

Questions also arose after the then St. Petersburg Times began reporting on the case and published an in-depth investigative article in 2007.

Alice Scott's testimony came under scrutiny after her ex-husband, Ricky Scott, told the St. Petersburg Times that she had a tendency to twist the truth. "No way Alice could've seen and heard from that little bathroom window what she said she heard and saw at the Schofields' that night," he alleged to the St. Petersburg Times reporters.

When reporters later questioned Alice Scott about her ex-husband's statement, she explained, "When I couldn't see and hear from the bathroom window that good, I walked to the screened porch where I could," which differed from her testimony in Schofield’s trial.

"She never said that at trial," Gilbert King, a Pulitzer-prize winning author who is the host of a new podcast about the case, "Bone Valley," told "20/20." " That was all new."

When asked about Alice Scott’s statement to the St. Petersburg Times, Jerry Hill told “20/20” that he believed Alice Scott was “credible” at the time that she testified and that his investigators verified her account.

“We had no less than three separate individuals go confirm that she could actually see what she said she saw, from where she said she saw it,” he said.

Leo Schofield's new defense team requested a trial based on the fingerprint evidence. During his 2010 deposition with Leo Schofield's attorney's, Jeremy Scott admitted to being a car stereo thief in the area during that time, but denied killing Michelle Schofield.

The request for a new trial was denied, as the court found that Scott's fingerprints alone would not likely have led to an acquittal on retrial and ruled there were no issues with the trial evidence that would have led to Leo's exoneration.

The decision devastated the Schofields, their attorney and other supporters.

"This was personal to me. I knew then the same thing I know now: Leo's an innocent man and it just hit me to my core," Cupp, now a circuit judge in Florida, told "20/20."

In 2016, Leo Schofield's defense attorney Andrew Crawford spoke with Jeremy Scott by phone and claimed that Scott confessed to him that he was responsible for Michelle Schofield's murder. The conversation, however, was not tape recorded.

"This is a huge deal, what Jeremy is telling me, because never before had he ever admitted any involvement in the homicide," Crawford told "20/20."

When questioned by state investigators, Jeremy Scott denied confessing but said he would take the rap for any murder if paid $1,000.

“Jeremy Scott, he's a red herring,” Jerry Hill said, “but he's the only herring they've got. And so they're going to stick with it.”

In 2017, Crawford enlisted an investigator to interview Scott again, this time with a tape recorder.

It was during this interview that Scott claimed that Michelle Schofield offered him a ride, and there was a struggle after a knife fell out of his pocket.

"Next thing I know, I lost it. I done stabbed her," Scott said during the interview. "I'm like panicking now because I don't know what just happened."

Crawford teamed up with The Innocence Project of Florida and made another request for a retrial, which led to an evidentiary hearing.

An emotional Jeremy Scott took the stand and testified that he killed Michelle.

During cross-examination, the prosecution pointed out multiple times over the years where Scott denied any role in Michelle Schofield's murder, as well as certain details that he could not recall or got wrong in his testimony, such as the clothes she wore that night.

The hearing took a dramatic turn when Scott was presented with Michelle's autopsy photographs, at which point Scott stated "I didn't do that."

"They took that as a flip flop that he recanted," Crissie Schofield said.

However, on redirect examination, Scott affirmed to the court that he did in fact kill Michelle.

"I killed her," he said.

Ultimately, Leo was again denied a new trial. The court ruled that the evidence did not meet the legal threshold for a new trial, and also made a finding that the testimony of Jeremy Scott was not credible.

An appeals court upheld the decision in 2020.

"I wish I could come up with a better word than devastation and disbelief and just madness. There's no way to understand it," Crissie Schofield said of her reaction to the court decision.

In 2018, Gilbert King, author of the Pulitzer Prize-winning book, Devil in the Grove, which led to the exonerations of four innocent men, was at a conference of circuit judges in Naples, Florida, when he was approached by Cupp and given information about Leo Schofield's story and his case.

Since then, King , along with "Bone Valley" researcher Kelsey Decker, has been investigating the case and working on a Lava For Good 9-part true crime podcast on Leo's story, "Bone Valley," that launched Sept. 21, 2022. Lava for Good is run by Jason Flom, one of the founding board members of the Innocence Project and a well known advocate for wrongly convicted.

Scott was recently interviewed for the podcast and claimed to Gilbert King that “Leo [is] innocent. That man didn’t do nothing. He’s innocent.”

During her exclusive TV prison interview, “20/20” co-anchor Amy Robach played Jeremy Scott's recording for Leo Schofield.

"I have a lot of anger about it. He murdered my wife," he told Robach. "It's a hard thing to forgive."

Leo Schofield is eligible for parole next year, and even if he does get out on parole Crissie Schofield said she is insistent on clearing her husband's name.

"It doesn't end with Leo getting out. This is Michelle's story," she said.