Later this month, there will be a hearing in Mississippi regarding a new murder trial for 33-year-old Kennedy Brewer.

Brewer stands accused of the1991 murder of Christine Jackson, the 3-year-old daughter of his then-girlfriend.

Brewer was initially convicted of raping and strangling Jackson to death in 1995. He was sentenced to death, and has spent the last 12 years on death row.

Brewer was convicted largely due to the testimony of Dr. Michael West, a dentist in Forest County, Miss. West is a self-described forensic odontologist, or bite mark analyst. He has testified in dozens of cases over the years, almost always for the prosecution. West testified at Brewer's trial that he found 19 bite marks on Christine Jackson's body which matched Brewer's teeth. West claims he could make the identification because of a chip in one of Kennedy Brewer's top teeth, and because Brewer's upper teeth are sharper than his lower teeth. A defense expert countered that the marks were actually insect bites—the result of Jackson's body being outside for two days before it was found.

The jury found Dr. West more credible. And that's a big problem.

Forensic odontology is an imprecise field. It often draws heavy scrutiny from other forensics experts. There's a troublingly long list of cases in which someone convicted on the word of a bite mark expert was later exonerated with improved DNA testing. In 1999, one forensic odontologist tested his colleagues with a sample crime scene bite mark during a conference workshop. Six of 10 wrongly traced the bite mark back to an innocent person.

But even in an already imprecise field, Dr. Michael West has taken forensic odontology to bizarre, megalomaniacal depths. West claims to have invented a system he modestly calls "The West Phenomenon. n it, he dons a pair of yellow goggles and with the aid of a blue laser, he says he can identify bite marks, scratches, and other marks on a corpse that no one else can see—not even other forensics experts.

Conveniently, he claims his unique method can't be photographed or reproduced, which he says makes his opinions unimpeachable by other experts.

Using the "West Phenomenon," West once claimed to have found bite marks on a decomposed woman's breast that previous pathologists had missed. In another case, he claimed to have positively traced a half-eaten bologna sandwich at the murder scene to the defendant's teeth based on bite marks in the sandwich. The defendant was convicted, but the case was later tossed out when West admitted to disposing of the sandwich after studying it. Because no one can replicate his methods, West said, the sandwich was no longer necessary.

In other cases, West claims to have found bite marks on bodies that had been submerged in swamps for weeks, and on others that had been buried for well over a year.

West has also been influential in preventing the state of Mississippi from adding some much-needed oversight to its forensic experts—likley because any sort of standards at all would end his career as an expert witness. In the mid-1990s, he served as the elected coroner for Forest County, Miss. At the time, the state medical examiner in Mississippi, a doctor named Emily Ward, was trying to institute some standards in the way autopsies were conducted in the state, including requiring minimal training and continuing education for the state's coroners.

West, with the help District Attorney Forest Allgood—the man who prosecuted Kennedy Brewer, and who has relied on West's testimony to secure convictions for years—led a revolt against Ward that ended with her resignation. The position of state medical examiner in Mississippi has remained vacant ever since.

West has received his share of media scrutiny, including exposés in Newsweek and on 60 Minutes. A 1994 article in the National Law Journal reported that when one defense attorney asked West on the stand about his rate of error, he replied that it's "something less than my savior, Jesus Christ."

Dr. West has compared his virtuosity in bite mark analysis to the musical talent of Itzhak Perlman. In his 60 Minutes interview, he boasted of a phrase he uses at trial that he considers his trademark: "Indeed, and without a doubt." It expresses a level of certainty that other forensic experts say simply isn't compatible with sound scientific analysis.

Defense attorney John Holdridge, now with the American Civil Liberties Union, told the National Law Journal, "I know of five other convictions he was involved in, all of which were death penalty cases." After the media exposés and persistent work of Holdridge, West resigned from two professional organizations, and was suspended for a year from another.

Despite all of this, Mississippi's State Supreme Court affirmed Kennedy Brewer's conviction in 1997 in an opinion that validated Dr. Michael West and his status as a bite mark expert, even while acknowledging his one-year suspension from the American Board of Forensic Odontologists (still in effect at the time of the Brewer trial), and that his testimony was thrown out in the bologna sandwich case.

Nevertheless, the court found, Dr. West still possessed the "knowledge, skill, experience, training and education necessary to qualify as an expert in forensic odontology."

In 2002, Kennedy Brewer's lawyers were able to get the state to conduct DNA tests on the semen found inside Christine Jackson's body. At the time of his original trial, the semen sample was too small for DNA testing, and Brewer's lawyers had to fight to keep it from being destroyed. More advanced technology enabled the smaller samples to be tested, and in 2002, Mississippi's crime lab found the semen actually belonged to two separate men. But neither of them was Kennedy Brewer. Brewer's attorneys are now looking into a similar murder of another little girl at about the same time and in the same area that Christine Jackson was killed.

Based on this new evidence, Kennedy Brewer was awarded a new trial. But prosecutors still refuse to exonerate him or release him from prison. Instead, they're going to try him again. And they're going to use Dr. West again. West has said in interviews that he stands by his analysis, and that his bite mark expertise indicates Kennedy Brewer was still involved in Christine Jackson's death, even if his semen wasn't a match with that found at the crime scene (when reached at his private dental practice, West said he was "not interested" in an interview for this article).

There are other problems with Dr. West's examination of Jackson, including a video never shown to the original jury that the trial court judge noted showed West and his assistants acting "rather callous" during the examination, blaring "inappropriate" music during the procedure, and "carrying on conversations" unrelated to the examination.

The Kennedy Brewer case and Dr. Michael West are symptomatic of a larger flaw in our adversarial criminal justice system—the use of expert testimony to explain complicated scientific evidence. A charlatan like Dr. West, who has little respect from his peers, can with charisma, personality, and impressive-sounding credentials convince a jury to take his word over that of an expert far more careful and deliberate in his analysis. In some cases, indigent defendants can't afford to hire their own experts at all, leaving a state's expert like West as the only testimony on the available forensic evidence.

Forensic scandals have been troublingly common of late, with phony experts, fake results, and incompetent testing recently uncovered in Virginia, Maryland, Kansas, Illinois, and Texas, to name just a few. Courts need to take a more active role in weeding out the Michael Wests of the world before they ever take the witness stand.

But professional organizations also need to be more vigilant about policing their own. Dr. West's peers should more vocally have questioned his methods long before he was permitted to testify more than 70 times in courts across the country. One would think they'd step up their standards to protect the integrity and reputation of their profession. But these continuing scandals suggest another, more urgent reason: to prevent bad science from sending innocent people to prison.

Radley Balko is a senior editor for reason. A version of this article originally appeared at FoxNews.com.