July 21, 2012 10:00 PM

"48 Hours" probes Missouri murder mystery

Two long months passed after the court hearing. Josh Kezer sat in prison, afraid to get his hopes up. Then, late on Feb. 17, 2009, Judge Richard Callahan issued his ruling.

"I've spent my life in the justice system," Judge Callahan said. "And so I was embarrassed for our system."

"Did the system make a mistake in the case of Josh Kezer?" Moriarty asked.

"The system made a big mistake in the case of Josh Kezer."

Judge Callahan, now the U.S. attorney for the eastern district of Missouri, was so disturbed by what he saw that he did something very unusual: instead of ordering a new trial, he went ahead and declared Josh Kezer an innocent man.

"As you sit here today, do you believe that Josh Kezer had anything to do with the murder of Michelle Lawless?" Moriarty asked.

"Absolutely not," Judge Callahan replied. "I believe he's innocent. And I so found."

"I let out this just roar," Kezer said. "I mean, I just let it out. I yelled. I shouted with everything I had in me."

The very next day, Josh Kezer walked out of prison - a free man for the first time in 16 years.

He hugged his mother and he hugged Jane Williams, the social worker who had championed his case.

"For years, he had had to carry that he was a monster killer who brutally killed someone, which was not true," Williams said.

Then Kezer turned to Sheriff Rick Walter. "I wanted to thank him personally for what he done," Kezer told Moriarty.

Both the prosecutor - Kenneth Hulshof - and former Sheriff Bill Ferrell have declined "48 Hours'" requests for interviews, but in court documents, Ferrell denies any wrongdoing and Holshof has said publicly that he still believes Kezer's guilty.

"I think we've done the right thing and, and we move on and try to find out who done this," said Sheriff Walter, who is determined to find the killer of Mischelle Lawless, still deeply mourned by her family and friends.

Melissa Gaines misses their friendship. "… just being able - because you could tell her anything, and she wouldn't judge you. And if she loved you, she loved you."

But someone hated Mischelle enough to kill her. Sheriff Walter still believes it is someone she knew.

"There's people of suspicion," he said. "We have right now about six or seven different people that, you know, we're definitely interested in, and we're looking at."

On that list is Mark Abbott. "Still today, I'm a No. 1 suspect in this murder, am I or am I not?"

Once a star witness for the prosecution, Abbott's account of the night of the murder raised questions, starting with what he said he did when he found Mischelle in her car.

"I just reached in the window and I grabbed her and she came up," Abbott said.

What's wrong with that story? The side window was only partly open, not wide enough, said the sheriff, to fit Abbott's story.

"You couldn't reach through the window and grab somebody and set 'em up, not the way he said," Walter explained.

When asked if he killed Mischelle Lawless, Abbott said "No."

"But there's a lot of people in this town who think you did," Moriarty remarked.

"A lot of people think I did," he said nodding his head in agreement.

"I've also spoken to a lot of people who've said you bragged about it," Moriarty said.

One of them was Ron Burton, a gun shop owner and long-time friend of Abbott's family. Burton remembered one chilling conversation with Abbott soon after Kezer was convicted.

"He said, and I quote, 'I took care of the bitch.' And that's what he said. And he kind of had a smirky little grin on his face," Burton recalled. "And I'll never forget it, because it shocked me."

When asked by Moriarty if Burton thought Abbot was kidding, he said, ""No. No, I don't."

Abbott denied ever saying that and said Burton was "lying."

There is also an affidavit from a narcotics detective who said Abbott told him that he didn't kill Mischelle, but watched another man do it.

To that Abbott said, "No. He's full of s--t."

"Why would so many people think you're capable of something like this, that they'd point the finger?" Moriarty asked.

"I don't know what I did to anger 'em like that."

"They're pointing the finger at you. Why?"

"I do not have an answer to that. I do not."

Abbott said he never met Mischelle, but her close friend, Melissa Gaines, had a different recollection. When asked if Mischelle ever mentioned a Mark Abbott, Gaines said, "Yes she did."

"She had said that she had met Mark, Mark Abbott, one of the Abbott boys, and thought he was a good looking guy. And I told her, 'Mischelle, you know, don't mess with either one of the Abbott boys, you know better than that.'"

In fact, there are two Abbott boys and they're identical twins.

Said Sheriff Walter, "Those boys, they would change places with each other from little boys on. You can't tell them apart."

Which is why to this day, the sheriff isn't absolutely sure which Abbott brother came in to report finding Mischelle. Two people in the sheriff's office say it was his twin, Matt.

"So was Matt involved? Was Mark involved? Matt says he never was, but yet we have two people that say he walked in and reported it. They have him down as Matt Abbott. So you know, that could be a conspiracy, couldn't it?" Sheriff Walter said.

Mark and Matt Abbott were convicted on federal drug charges in 1997, making some people in town wonder if maybe Mischelle Lawless had something on them.

"There's a lot of theories out there," Sheriff Walter explained. "You know, one of 'em was that she had information on their drug dealing, and there's a lot of money involved in that. …That's motive enough for somebody to kill somebody."

Along with Abbott, Sheriff Walter hasn't ruled out Leon Lamb - the last person to admit to seeing Mischelle Lawless alive.

"Did you have anything to do with Mischelle Lawless' death?" Moriarty asked Lamb.

"Not at all. I loved her."

"You know that your DNA was found under her fingernails?"

"Yes, ma'am."

"And how do you explain that?"

"We had sex that night and we were both pretty passionate people, so you know, time and again she scratched me during sex."

But Lamb confirmed what Mischelle wrote in her diary: that the couple had frequent arguments, especially when he saw her with other men. And in fact, the night of her murder, Mischelle had run into Lamb while she was driving around with male friends.

"Did that bother you?"

"It did," Lamb said. "You know, because we had been together for three years."

"Did she leave the house upset with you or angry with you at all?"

"No, not at all. I mean, we - like I said, we hugged, kissed and said our goodnights and that was it."

Abbott and Lamb are only two of a half-dozen suspects. And Sheriff Walter needs more than theories and speculation. He needs hard evidence.

To find it, he went all the way to the Netherlands, to a place known as the "crime farm."

© 2012 CBS Interactive Inc. All Rights Reserved.
5 Comments +
48 Hours 48 Hours for iPad® A perfect companion to TV's most popular true-crime series.
48 Hours on Facebook