The FBI is notifying hundreds of defendants in 46 states that their convictions involved flawed expert testimony. It now admits that nearly every examiner in an elite forensic unit overstated hair matches that favored prosecutors.
This is one of the country's largest-ever forensic scandals and includes dozens of death row convictions, reports CBS News correspondent Julianna Goldman.
Cleveland Wright spent 28 years -- almost half his life behind bars -- serving time for a 1978 murder.
His conviction, it now turns out, was based on a false FBI hair analysis.
"I didn't know anything about forensics. I didn't know too much about law when I got arrested and locked up, but I just knew I was innocent," Wright said.
New data shows he is not alone.
The Innocence Project and the National Association of Criminal Defense Lawyers found from the 1970s through 1999, in 268 cases where FBI hair analysis led to a conviction, 257, or 96 percent, had errors in analysis.
Eighteen of those defendants were living on death row -- 12 had been executed.
"Finding a suspect's hair on a victim, or vice versa, finding a victim's hair on a suspect, that's the kind of linkage that prosecutors love," forensics expert Larry Kobilinsky said.
He said microscopic hair analysis was thought of as cutting edge science, even though there was no way to scientifically identify a match before DNA testing.
Still, he said, if an FBI agent testifies, juries listen.
"There's a certain aura about FBI agents. They are very sharp, and very trustworthy; it doesn't mean their experimentation was done properly," Kobilinsky said.
Wright was exonerated in 2014, but has not been compensated for his 28-year prison term.
He remains hopeful for his future and the hundreds of others who may have been wrongfully convicted.
"I just thank God for the people that's looking into these cases; not only mine, other people that are in the same situation that I am in, you know, they need help too, they crying out too, their heart is crying out also," Wright said.
Errors do not mean there was no evidence of guilt, but defendants may have grounds for appeal.
The FBI released a statement Sunday saying they "are committed to ensuring that affected defendants are notified of past errors... and will continue to do so until all of the cases are addressed."