Over the course of Sherwood Brown’s arrest, conviction and 28 years in prison, there were numerous points at which Mississippi could have done right by him, or at least ended his torment. It didn’t happen until August, when DNA testing finally convinced a court that Brown likely did not commit the 1993 triple murder for which he was convicted and sentenced to death.

Brown was convicted mostly because of the notorious forensics charlatan Michael West, who claimed to have matched a mark on Brown’s skin to the teeth of one of the murder victims. In the mid-1980s, West, a folksy, oddly charismatic dentist from Hattiesburg, Miss., began pitching himself as a forensics wizard, claiming he could find evidence no one else could see, and match it to the culprit when no one else could.

It was hokum. Brown is at least the fifth person convicted by West’s handiwork to be exonerated, the third to be freed from death row, and the second to be freed from death row this year. In January, Eddie Lee Howard was exonerated after 26 years in Parchman Penitentiary.

Even before Brown was convicted, West’s career should have been over. In 1990, police suspected a man named Larry Maxwell of a triple murder near Meridian, Miss. Maxwell was seen on video going to work during the time the crime was allegedly committed. However, West claimed that he could match one victim’s stab wounds to a specific knife found nearby, and that he found marks on Maxwell’s hands that could only have been caused by gripping and stabbing someone with the same knife — to the exclusion of all other knives.

These marks weren’t visible to anyone else — just to West, and only when using an ultraviolet light technique he claimed to have invented. Later, at an evidentiary hearing, West admitted he had inadvertently exposed the film containing the photos of Maxwell’s hands under the ultraviolet light. Instead, West had Maxwell put his hands on a photocopier, and used a marker to draw in the incriminating marks from memory.

To his credit, the judge in Maxwell’s case refused to allow West to testify. Because West was the only real evidence against Maxwell, he was released after two years in prison. No one was ever convicted in the murders.

But rather than a cautionary tale, this would be one of the few times West was ever denied by a judge. For some prosecutors, West’s quackery wasn’t a flaw, it was a feature. Juries found him persuasive, and he was clearly willing to say just about anything to get a conviction.

Tellingly, West never generated leads in cold cases. It was only after the police had already settled on a suspect that he’d swoop in, find marks invisible to the naked eye and provide the slam-dunk match to close the case. In the 1980s and ’90s, he was the subject of doting media profiles touting his innovative methods. Few forensic specialists and organizations called him out. When two different Mississippi state medical examiners did speak up, prosecutors and law enforcement officials rallied to West’s defense. Both examiners ultimately resigned in frustration.

West actually never appeared at Brown’s trial. Another bite-mark analyst used West’s examination and notes to testify against Brown. That’s because West was busy testifying against another man, Kennedy Brewer. West claimed to have found bite marks on a young rape and murder victim that could have come only from Brewer. As with Brown, the jury convicted Brewer and sentenced him to die. Like Brown, Brewer was innocent. The number of experts who can claim to have sent two innocent men to death row is pretty small. Michael West did it in a single week.

When in 2001, new DNA testing excluded Brewer as the source of the semen found in the girl he’d been convicted of raping and killing, the district attorney cited West to insist that Brewer must have participated in the crime, even if he didn’t commit the rape. So Brewer remained in prison until 2008, when Brewer’s attorneys were finally able to match the killer’s DNA against a database of known offenders. The man with the matching profile soon confessed — and confirmed he committed the crime alone.

Worse, the killer also confessed to another rape and murder in 1990, for which another man, Levon Brooks, had also been wrongly convicted. In that case, West not only falsely implicated Brooks, he examined the teeth of the real killer and explicitly “excluded” him as the source of the marks. It’s one of two cases that we know of in which West’s misidentification allowed the real perpetrator to kill again.

Over and over, Mississippi officials were put on notice about West. As the years wore on, West was eventually suspended or barred by several professional forensic and accrediting organizations. (He claimed they were simply jealous of his talents.) In 2009, I obtained a video in which West appeared to use a dental mold of a suspect’s teeth to create the very bite marks on the corpse that he’d later attribute to the suspect. Another similar video emerged two years later.

But Mississippi prosecutors kept looking the other way — the state kept defending convictions won with his testimony, and judges kept upholding those convictions. No one had much incentive to speak up. One state supreme court justice who did try to warn about West was hit with attack ads accusing him of voting to free a “child killer” — Levon Brooks. Mississippi’s chief justice at the time would later say, after retiring, that the court’s refusal to sideline West was among the biggest regrets of his career.

Former Mississippi attorney general Jim Hood, who held the office during the Brooks and Brewer exonerations, conceded at times that West wasn’t a credible witness. Yet Hood’s office still defended convictions won with West’s testimony — not by asserting West’s credibility, but by arguing that the petitioning prisoners had already challenged that credibility in court and lost, and therefore were procedurally barred from challenging West again.

So though Brown is finally free, most of West’s other victims remain in prison. That’s because our court system has prioritized preserving the finality of verdicts. Because courts tend to consider these cases in isolation, what an expert may have said in other cases isn’t usually relevant. If the testimony in the case under consideration is within the boundaries of what courts have traditionally considered scientifically credible, they won’t reopen the case.

Reopening all of West’s cases would also require a major concession, not only that the courts were wrong about West but also that the very way courts authenticate experts is deeply flawed. Ideally, our legal system would acknowledge that a human-made, human-run system will inevitably be flawed and strive for the authentic legitimacy that comes with correcting its mistakes. Instead, the courts cling to the faux legitimacy that comes with refusing to admit mistakes. Typically, only DNA can shatter that illusion.

It’s unlikely that West will ever be held accountable in any real way. In 2017, a federal appeals court ruled that he and other experts are protected by qualified immunity, even for grossly negligent testimony that sends an innocent person to prison. To even get in front of a jury, a wrongly convicted person must show a witness such as West knew his testimony was false when he gave it — an almost impossible standard.

In the end, Michael West is only a symptom, though an especially egregious one. The courts have long been tainted by ignominious experts. Most aren’t as brash and audacious as West. Most are smart enough to dial it back after encountering scrutiny. Yet despite the obvious, ample warnings, despite the exonerations and suspensions, it still took 15 years to clear Kennedy Brewer, 16 years to clear Levon Brooks, 26 years to clear Eddie Lee Howard and 28 years to clear Sherwood Brown.

And those are the “good” outcomes. Because to this day, the state of Mississippi has shown little interest in learning just how much damage Michael West may have done.