SPECIAL REPORT -- During the 26 years that James Preston spent incarcerated for murder, he always told his family that he didn't commit the crime.
Now, the FBI says their analyst's testimony about key hair evidence in the case exceeded the boundaries of science, raising the possibility that Preston, who died in custody, was wrongfully convicted if not, as his family believes, innocent.
"I sat with him as he passed away and I kissed him and I told him, I said, ‘I'll let everybody know that this is not right, this is not true, and you shouldn't be here,'" his brother, Erick Preston said. "That's all they had from the FBI lab, a hair with ‘negroid features'… but he swayed it to make it look like it was my brother's."
The FBI's review of Preston's file is part of a nationwide effort by the Department of Justice and the FBI to re-examine the testimony of FBI forensic experts in serious cases like murder and rape, all done before the advent of DNA testing. More than 2,000 cases involving hair analysis are being reviewed.
James Preston was arrested just a few days after Thea Pierce's body was found in the bathtub of her Lawrence apartment in January 1983. Preston, a musician, lived downstairs from Pierce. She had been bound at the hands and feet, strangled with a scarf and apparently had been raped.
Several hairs were taken to the FBI lab for analysis, including two found in the bathroom that were described, in the language of the time, as "negroid." Police obtained a warrant to take hair samples from Preston, who was black, so they could compare them to the hair found at the scene.
"He called me from the police station and said, ‘I don't know what's going on, they're taking hair from my chest, they're taking hair from my head,'" his brother recalled.
An FBI analyst used a microscope to compare the crime scene hairs with Preston's.
When the case went to trial later that year, the analyst first told the jury that the microscopic comparison he did "cannot be used as an absolute method of personal identification" – a statement the FBI now says was an appropriate way to describe the limits of forensic hair analysis.
But under cross examination, the analyst went further.
"Well, it's the combination of these characteristics that makes the hair unique," he told the jury, according to a transcript of his testimony.
As unique, the analyst went on to testify, as a person's face.
Those last statements, the FBI wrote in a letter last year, were improper because the analyst "stated or implied that the evidentiary hair could be associated with a specific individual to the exclusion of all others."
FOX Undercover showed records of the Preston case to Nancy Gertner, a retired federal judge who has written about the need to apply more scientific rigor to forensics. She said it's unclear from what she has reviewed to say whether Preston was wrongfully convicted or not.
"We know there was a problem with the testimony. We know that needs to be examined, we know it means that it could mean that they have gotten the wrong man," Gertner said.
Especially problematic with testimony about hair analysis, Gertner and others say, is when experts would find similar characteristics between two hair samples but then go on to say that the hairs had to have come from the same person. Hair analysis is not precise enough to support that conclusion and, in some cases, DNA testing has shown that testimony to be outright wrong.
"The examiner would just look at "A" hair and "B" hair and draw a conclusion, and then when we had DNA testing we could now see, was that true? And it turned out that numbers of them were erroneous," Gertner said.
Expert testimony of all stripes is particularly persuasive to juries, Gertner said.
"When someone out of your circle comes forward and says, ‘This is what the evidence is, this is what the expertise suggests,' it has an enormous impact," she said.
The federal government's review of cases was sparked after DNA testing exonerated three men in the Washington D.C.-area, all of whom had been convicted and imprisoned with the help of hair analysts' testimony.
In Preston's case, the hair analysis wasn't the only thing working against him.
Damaging testimony came from two witnesses who both lived in the building with Preston and Pierce. One witness said she bumped into Preston outside Pierce's door, putting him in the vicinity of her apartment.
Another witness said that, around the same time as the other witness heard Preston outside the victim's apartment, she heard sounds of a struggle coming from Pierce's apartment.
Prosecutors found a motive, too. Preston had stolen checks of Pierce's from her mailbox, a theft that postal inspectors were already investigating.
Still, Preston's lawyer at the time, Willie Davis, was confident his client would be cleared.
"Was it a weak case?" FOX Undercover reporter Mike Beaudet asked Davis.
"Very weak, from the prosecution's point of view," Davis replied.
But Davis' confidence would not last long. The jury convicted Preston of second-degree murder.
The defense team wasn't the only one surprised. In an unusual move, the trial judge set aside the jury's verdict and ordered a new trial.
"He felt that the evidence was not sufficient to sustain a conviction," Davis said.
So the case was re-tried in 1985. During opening statements, the prosecutor told the jury that a hair at the murder scene "'matched the head hairs of James Preston,'" court records show. The analyst also testified again, testimony that still being reviewed by the FBI.
The verdict was the same: guilty, second degree.
"Do you think an innocent man went to prison?" Beaudet asked Davis.
"Yes I do," Davis replied. "I thought so from the beginning."
Not everybody thought so, though. Pierce's brother, Tracy Trott, told FOX Undercover the FBI's letter does nothing to dissuade them from believing Preston killed Pierce, a single mother. The point to his two convictions as well as a partial confession he later made to the Parole Board as proof of his guilt.
"This new information has no real effect on our family," Trott said in a family statement. "The damage was done 30 years ago and that cannot be undone. My mother and father were severely affected by Thea's murder up to their death not to mention a son having to grow up without his mother. To be honest, we are glad Mr. Preston is dead and will never be a threat to any other innocent victim. He was a monster that preyed on an innocent female. Even though he spent the last 25-30 years in prison, he made out better than my sister."
Preston's family says he told them he was going to falsely confess to the Parole Board so he could be released, but after he denied sexually assaulting Pierce the board denied his bid for freedom.
Preston also left behind his own child, a daughter he had with Mary Ann Walker, who was living with him when he was arrested.
"My whole world just shattered," Walker said. "He told me after he got convicted to go ahead and live my life. He knew he wasn't getting out. He said they want me for some reason." "Did you always believe that he was innocent?" Beaudet asked her.
"Always. Without a doubt. And that's what I told her," she said, referring to her and Preston's child.
That child, K.C. Preston, is now 31 years old. She grew up knowing little about her father.
"All we had was letters and one phone call, and that was when I was 18 and he was singing me happy birthday on my 18th birthday," she said.
Preston died in 2009 after being denied three times by the Parole Board for release. At his last hearing, in 2008, he was so sick he couldn't speak for himself.
"What was that like for you, all these years later, to hear the FBI screwed up?" Beaudet asked Preston's daughter.
"I feel like I've been robbed of the chance to even know my dad," she said. "He missed a lot."
"Do you think he was innocent all along?" Beaudet asked her.
"I do now, yes," she said. "Especially after that letter."
Essex County District Attorney Jonathan Blodgett, whose predecessor prosecuted Preston, declined to be interviewed but a spokesperson released a statement pointing to the other evidence besides the hair that was used to convict Preston, including the witnesses who placed Preston near the scene of an apparent fight as well as the motive of the stolen checks.
"This and other evidence was submitted to two juries, and both convicted Preston of second-degree murder. After reviewing that evidence, the Appeals Court had "no doubt that the evidence, viewed in its entirety, although circumstantial, warranted a rational jury in finding beyond a reasonable doubt that Preston was the killer," the DA's statement said.
Now Preston's family wants DNA testing done on the hairs found at the scene to say once and for all, according to science, whether he was the killer. The DA's office said they would not oppose DNA testing if testable hair samples still exist. None have been found so far.
© 2016 Cox Media Group.