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A bite mark, a forensic dentist, a murder: how junk science ruins innocent lives

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Charles McCrory is haunted by a memory from his 1985 trial in which he was accused of murdering his wife, Julie Bonds, in a bloody attack at their home in Andalusia, a small town in deepest Alabama.

What haunts him is the look on the jurors’ faces as they listened to the testimony of the prosecution’s star witness, a dentist named Richard Souviron. He was a founding father of a cutting-edge branch of forensic science known as bite-mark analysis, which claimed to be able to identify violent criminals by matching their unique dental patterns to the bite wounds on victims’ bodies.

McCrory was expecting Souviron’s evidence to be nuanced. In his initial report, the dentist had been cautious about what could be deduced from two puncture marks found on the upper right arm of Julie’s body, saying that the injuries were insufficiently distinct to allow a positive match with the perpetrator.

But that was not what he told the jury.

When Souviron was asked whether the two marks were teeth marks, he said: “Yes”.

Then the prosecutor asked him: “In your expert opinion, based on the evidence presented to you, were these teeth marks made by Charles McCrory?”

“Yes,” the dentist replied.

McCrory remembers vividly the sinking feeling he experienced in that moment, given the glaring contrast between Souviron’s initial report and what he was now saying in court. “I was in disbelief at his testimony being so different,” he recalled. “I knew it was extremely damaging to our case. You could see it in the eyes of the jurors.”

McCrory shared his recollections of that critical instant in a handwritten letter he sent to the Guardian earlier this month.

Facebook Twitter Photograph: Courtesy of Charles McCrory

It was composed from an Alabama prison cell where he is serving a life sentence, still protesting his innocence, 37 years after the jury returned a guilty verdict based on that one simple word: “Yes.”

•••

McCrory’s current lawyer is Chris Fabricant. Together with co-counsel, Mark Loudon-Brown, Fabricant is representing the prisoner in an epic battle to clear his name almost four decades after he was identified as the source of those supposed teeth marks on his wife’s body.

For Fabricant, this is much more than a routine criminal case. It is the latest chapter in a personal voyage that began 10 years ago, when he embarked on his exploration of the murky waters of forensic science.

Facebook Twitter Charles McCrory with his wife, Julie Bonds, and their son Chad. Photograph: Courtesy of the McCrory family

Fabricant is director of strategic litigation at the Innocence Project, the formidable New York-based non-profit that for 30 years has used DNA evidence to overturn hundreds of wrongful convictions. He is an authority on the perils and limitations of science as it has been applied to criminal justice.

In that role, he has become one of forensic science’s most piercing critics. He has highlighted the part played by “expert witnesses” – forensic dentists, ballistics experts, FBI laboratory agents, lie detector examiners, blood stain investigators – in inadvertently putting innocent people behind bars.

He has a word for it: junk science.

In his new book, Junk Science and the American Criminal Justice System, Fabricant explains what he means by the term. “Junk science sounds like science,” he writes, “but there is no empirical base for the ‘expert opinion’; it is subjective speculation masquerading as science.”

The world of junk science took off in the late 1960s and 70s – an era in which confidence about the ability of scientists to propel humanity to giddy new heights was unbound. If science could put a man on the moon, then surely it could do the much more mundane job of nailing violent criminals?

Fabricant told the Guardian that there were problems with the new forensic science techniques from their inception. The methods did not arise out of the usual scientific method that starts with a problem, develops an hypothesis to solve it, then tests it via empirical methods.

Rather, it turned the formula on its head. Start with a desired solution – banging up criminals – then work back to the science that would support it.

“Most of the new theories emerged not from a scientific laboratory but from a crime scene,” Fabricant explained. “An enterprising investigator would think, ‘Maybe I could match this suspect’s teeth to the bite on this victim’s nose – that would prove the suspect is the murderer’. Then off they’d go and find an expert witness who could back the theory up.”

The explosion in junk science began with forensic pathologists who, with the enthusiastic encouragement of the FBI’s legendary crime laboratory, began to invent a plethora of new forensic practices.

Facebook Twitter A latent fingerprints analyst demonstrates his process during a tour of the Department of Forensic Science in northern Virginia. Photograph: Getty Images

The new generation of techniques had this in common: they all claimed to be able to identify an individual perpetrator through forensic analysis of various types of crime scene evidence.

There was “hair microscopy” – the idea that a single hair retrieved from the scene of a murder could be put under the microscope and matched with high degrees of certainty to the suspect’s hair. There were lie detector tests sold under the portentous title “polygraphs”; voice spectrometry to identify a criminal through forensic deconstruction of their speech; “toolmark” analysis that sought to link marks found at a crime scene to a specific object – a pipe, perhaps, or hammer; and comparative bullet lead analysis that professed to be able to match a bullet found at the scene of a killing to the single box of bullets from which it originated.

As use of the new techniques began to spread across the US, the reputation of forensic pathologists soared. They were invited to attend specialist conferences around the world, and lauded as “medical detectives”.

Celebrity status wasn’t far behind. One of the earliest stars of the genre, New York’s medical examiner Dr Milton Helpern, was called “Sherlock Holmes with a microscope”.

His successor, Dr Michael Baden, was given his own HBO TV series in the 1970s. Autopsy showcased a new forensic technique each week, highlighting the wonders they performed in solving gruesome and knotty crimes. Baden later went on to be involved in high-profile cases such as the OJ Simpson trial and the autopsy of Michael Brown, the unarmed Black teenager shot dead by a police officer in Ferguson, Missouri.

Facebook Twitter The CSI team investigates a murder mystery on the TV show CSI: Vegas. Photograph: CBS Photo Archive/CBS/Getty Images

Following the rise of such celebrities, it was but a step to forensic science becoming infused into the popular imagination. TV shows that had lionized vice cops and FBI special agents now began to switch their soft-focus lenses on to forensic pathologists.

Forensic Files aired from 1996 to 2005. CSI: Crime Scene Investigation, a formidably popular show aired between 2000 and 2015, looked at how forensic scientists cracked the hardest criminal cases. Once this glowing view of forensics had taken hold of the small screen, it was inevitable that it would seep into the mindset of juries.

“These TV shows depict an unrealistic infallibility of forensic sciences which became part of our popular culture,” Fabricant said. “Jurors walk into court believing that if it is forensic science that ties this defendant to the crime, then the likelihood of their guilt is overwhelming.”

•••

With forensic pathologists soaking up so much glamorous TV coverage, it was only a matter of time before dentists wanted in on the game. By the late 1970s, as Fabricant chronicles in his book, “forensic odontology” was starting to emerge, pioneered by a small number of individuals who were portrayed as “swashbuckling crime fighters, handsome, fit, bawdy, prone to ghoulish humor, comfortable with dead bodies, brilliant. Men’s men.”

Fabricant quotes the Los Angeles Times remarking admiringly that one of those pioneers, Dr Gerald Vale, hadn’t fixed a tooth in years. “His job is to fill jail cells, not cavities,” the paper gushed. An industry newsletter said about Vale: “Instead of tracking down decay, he tracks down people!”

What united the group of 12 “founding fathers” of forensic odontology was the belief that bite mark evidence could be used as a new tool up there with fingerprints, toxicology and other established methods. But to be taken seriously, the pioneers needed to establish their reputation, and for that they needed to be recognized as a scientific specialism as worthy of respect as any pathologist.

They began in 1976 by forming an “odontology section” within America’s top professional forensics body, the American Academy of Forensic Sciences. Not content with playing second fiddle, they then created their own organization, the American Board of Forensic Odontology (ABFO). As icing on the cake, they granted themselves a fancy title: “diplomates”, they called themselves, signaling their specialist status as trained and authoritative experts.

So when Souviron travelled the country to appear as a star expert witness in criminal cases such as McCrory’s murder trial, he did so not as Richard Souviron, dentist from Florida, but as Dr Richard Souviron, board-certified diplomate and member of the ABFO.

How could a jury resist that?

“This was 1985, when to fly an ‘expert’ witness in from Florida was practically unheard of,” McCrory wrote in his letter to the Guardian, referring to his own trial. “No jury, as lay people, have the ability to genuinely question a supposed expert, especially back then.”

Facebook Twitter A photo taken by Dr Richard Souviron shows the injury on Julie McCrory’s arm alongside Charles McCrory’s dental mould. Photograph: Courtesy of the Southern Center for Human Rights

The problem was, bite mark analysis, like many of the new forensic techniques, was founded upon so much hot air. There are two stages involved in matching a wound to an individual perpetrator, and both of them are flakey.

The first is categorically to confirm that the wound is caused by someone’s teeth and not by some other sharp object. The second stage is to link the alleged bite mark to the dental pattern of the suspect, by taking a mould of the suspect’s teeth and comparing it to the wound.

Analysis in both those stages, contrary to the scientific method, is subjective. A study published in 2009 by New York scientists tested whether skin could accurately record the impressions left by teeth – the 3D-equivalent of a fingerprint – and found that it could not.

The scientists simulated 23 identical bites on a single piece of un-embalmed cadaver skin. They discovered that the bites produced 23 entirely different marks, each one bearing little resemblance to the rest.

A more detailed study in 2015, carried out by ABFO-certified forensic dentists themselves, asked 38 of their fellow “diplomates” to review photographs presented in real criminal cases where bite mark analysis had been used. Of the 100 cases they examined, the analysts reached unanimous agreement in only four.

These two experiments effectively toppled the entire house of cards upon which bite mark analysis had been erected.

In his book, Fabricant concludes that when forensic dentists presented juries with a “near certain” match between the marks on a victim and a suspect – as Souviron did at McCrory’s trial – all they were doing was expressing their own personal opinion.

•••

It is a paradox that it took science to overcome junk science. “Nothing else could have challenged it other than DNA evidence, because a clean DNA sample is indisputable,” Fabricant said. “DNA was like a truth serum that the justice system had never before been exposed to.”

Over the years, DNA analysis has demonstrated itself to be blessed with all the qualities that junk science claims to enjoy but lacks: reliability, certainty, accuracy, indisputability.

The DNA revolution was launched in 1992 when two young lawyers in New York City decided to take on the combined might of the criminal justice system just as it was getting into its mass incarceration stride.

Barry Sheck and Peter Neufeld founded the Innocence Project to take on cases where crime scene evidence allowed DNA testing to be carried out. They used it to expose wrongful convictions and secure exonerations – more than 200 to date attained by the Innocence Project alone.

As time passed, the group’s crack team of lawyers observed that in so many of the wrongful convictions, the prosecution had relied upon the testimony of forensic scientists. Almost half of the total of 375 exonerations that have been achieved by the Innocence Project and other groups using DNA evidence involved the misuse of forensic sciences.

The dawning realization that junk science might have put a vast mountain of innocent people behind bars has inspired the Innocence Project to make a historic revision of its mission.

As it approaches its 30th anniversary this year, the organization has decided to widen the net of cases that it takes on to include those where no DNA evidence is available.

That’s a big change in focus. Up to now, the Innocent Project has pinpointed its energies almost exclusively on DNA. But what about people who cannot call on DNA to prove their innocence, maybe because there were insufficient crime scene materials, or maybe because such materials were destroyed post-trial? Are those people to be abandoned with little hope of ever receiving justice?

“Those who can be exonerated with DNA evidence represent just the tip of the iceberg,” Christina Swarns, the executive director of the Innocence Project, told the Guardian. “Going forward, the Innocence Project will begin to accept non-DNA cases and we will approach them with the same tenacity, innovation and client-centered approach we brought to our DNA work.”

This is a significant paradigm shift for an organization that put the concept of wrongful conviction on the map, both in the United States and around the world. By widening its focus to include non-DNA cases, Fabricant believes it will herald “a new era of innocence litigation that will involve undoing the legacy of junk science”.

Which prompts the question: how many innocent people are out there?

“I shudder to think,” Fabricant said. “There are 2.3 million people incarcerated in this country. Even if the wrongful conviction rate were 1% , and that’s conservative, you are looking at tens of thousands of people.”

Fabricant is convinced that McCrory, who is now 62, is one of them. “Mr McCrory is obviously innocent, and he would be out right now if we had DNA evidence.”

•••

Julie Bonds was murdered on 31 May 1985 in her home in Andalusia, south Alabama. McCrory was not living in the house at the time – the couple had recently separated after 10 years of marriage; they had one son together.

McCrory and his father discovered her body after they called on the house, worried that she was not answering the phone. She had been badly beaten, and had a deep wound to her skull.

The 1985 McCrory trial was held just before DNA analysis came on stream – the first time DNA was used to convict someone was in Florida in 1987, while the first DNA exoneration followed two years later in Chicago.

Because it was presumed to serve no further useful purpose, all the crime scene materials collected in the Bonds murder investigation were destroyed – a routine event in pre-DNA days. That left no biological samples to test once DNA was commonplace.

Facebook Twitter Willard O’Neal hugs Tiffany Gobble, an investigator with the Innocence Project, after his release from prison. Testing on evidence from the crime scene failed to find his DNA. Photograph: Ian Maule/AP

Detectives investigating the Bonds murder actually found hairs clutched in the hand of McCrory’s murdered wife that conventional examinations conducted at the time ruled out as having come from him. But the hairs, along with everything else, were binned.

Other evidence also pointed to McCrory’s innocence. At the time of Bonds’ killing, a construction worker was being employed on a building project in the house next door. He wore a red bandana.

Five weeks after Julie Bonds was murdered, that same man was arrested for breaking into a different home and raping the owner. He served 20 years in prison. At that crime scene, officers found a red bandana.

Despite the inconsistencies in his case, McCrory was at a powerful disadvantage. Without the benefit of DNA to clear his name, he languished in prison for decades.

Meanwhile, however, bitemark analysis was beginning to unravel.

In 2009 – by which time McCrory had spent 24 years in prison – the National Academy of Sciences (NAS) released a 300-page report on the use of forensic science that sent what Fabricant called a “thunderbolt” across the criminal justice system.

It was searingly critical of 13 forensic techniques that were routinely being used in criminal trials. It reserved its most scathing denunciation for bitemark analysis.

Facebook Twitter A police officer dusts belongings for fingerprints. Photograph: Graham Turner/The Guardian

The report’s authors noted that the claim that dentists could positively identify a perpetrator by matching their dental patterns to marks on victims’ bodies had never been supported by any scientific study. Indeed, “no large population studies have been conducted”.

In other words, bitemark analysis was an unsubstantiated whim on the part of its inventors. The report concluded that there was “no evidence of an existing scientific basis for identifying an individual to the exclusion of all others”.

The combined impact of the NAS report and DNA evidence led to a renewed focus on criminal cases where bitemark analysis had been critical to the prosecution. Scientific certainty began to crumble. Exonerations mounted up.

Today, the tally of people who have been exonerated after wrongful indictment or conviction involving bitemark analysis stands at 35.

They include several of Fabricant’s clients: Keith Allen Harward, exonerated in 2016 after spending 33 years in prison for a rape and murder he did not commit; Stephen Chaney, exonerated in 2019 after 28 years behind bars; Eddie Lee Howard, exonerated in 2020 – 26 years inside.

They were the lucky ones.

David Wayne Spence was convicted of murdering three teenagers in 1982 after his teeth were matched to bite marks on the victims’ bodies. On 3 April 1997, he was strapped to a gurney and lethal drugs injected into his veins.

He went to his death insisting he was innocent.

•••

In December 2019, Souviron recanted his testimony. He had taken another look at the evidence in the case, considered it alongside the criticisms raised by the NAS report, and went on the record to say he had been wrong.

“While this testimony was understood by myself and others within my field as scientifically acceptable at the time of trial, I would not give [it] today,” he said in an affidavit. “As a forensic odontologist I no longer believe the individualised teeth marks comparison testimony I offered in his case was reliable or proper. I therefore renounce that testimony.”

The Guardian reached out to Souviron to ask him how he came to change his thinking so radically, but his office said he was not available.

The dentist’s reversal was sweet music to McCrory’s ears. “We knew a recantation from the state’s own witness, their only forensic witness, would eviscerate their case. At that point the only fair way forward would be a new trial,” the prisoner wrote.

McCrory duly petitioned for a new trial. With no forensic evidence of any sort, and with no other substantive evidence to rely upon, the state’s tank was running on empty. Even the prosecutors admitted that McCrory posed no harm to the public.

In April last year, on the eve of a court hearing to determine whether a new trial should be granted, the prisoner was offered a plea deal.

He could walk free, that very same day, on one condition. He had to plead guilty to his wife’s murder.

He declined the deal, opting to stay in his cell.

“That was an easy decision,” he wrote in his letter to the Guardian. “I did not murder her … I didn’t do it, and I’m not admitting to it.”

He added: “Someone murdered Julie. Someone knows who it is. We are seeking the truth, not falsely confessing to a crime I didn’t commit.”

Many people would find McCrory’s rejection of a deal that would have instantly set him free hard to comprehend. Fabricant is among them.

“I can understand it in an intellectual way, but as a human being I think after 36 years I’d want to go home,” he said.

•••

McCrory still hasn’t gone home. It has now been 37 years and counting. The bitemark case against him has been thoroughly debunked, but it turns out that doesn’t matter. Junk science proves to be scarily resilient – an invasive weed that grows rampant across the country, poisoning the criminal justice system as it spreads.

A few days after McCrory turned down the plea deal, an evidentiary hearing was held in front of Judge Charles Short in Andalusia, Alabama, to discuss the request for a new trial.

Souviron’s recantation was presented to the court, as was the testimony of three other forensic dentists who not only confirmed that the marks on Julie Bond’s body could not be matched to the prisoner, they said that the marks were not even caused by teeth in the first place.

Judge Short listened to this devastating argument, took in all the other evidence of McCrory’s innocence, then issued his ruling: there would be no new trial; McCrory would remain in prison.

Fabricant was uncharacteristically lost for words when he tried to describe his reaction to the judgment. “How can that be? How can that be? It’s preposterous. We are in 2022 and a judge is refusing a new trial even when the scientist in question has recanted. He is keeping an innocent man in prison based on nothing.”

Despite the knock-back, McCrory says he is keeping his spirits up. “I’m optimistic that justice will prevail,” he wrote at the end of his letter. “Every time we have run into a seemingly dead-end, a door has opened. We will not stop until we have the truth.”

Facebook Twitter Photograph: Courtesy of Charles McCrory

This will be scant comfort to McCrory, but he is not alone. Fabricant points out that bitemark analysis is still admissible in all 50 states of the union.

Three of the most influential bitemark cases where marks were matched to “guilty” perpetrators have all ended in exonerations. Yet the cases retain their status as “good law” and continue to be cited as precedent in court to this day.

In the wider world of junk science, not only do discredited techniques continue to be used, but new techniques keep popping up. Fabricant rattles off three examples of forensic innovations that are beginning to ring alarm bells.

There’s forensic podiatry, where foot doctors claim they can identify a perpetrator from their gait; cadaver dogs which are supposedly able to sniff out the presence of a human corps even years after the body may have been present; and ShotSpotter, an audio system that purports to be able to isolate the sound of gun shots from other noise in urban areas.

If that all sounds depressingly familiar, that’s because it is.

“Our goal in the Innocence Project is to go out of business – we aspire to become unnecessary,” Fabricant said. “It appears we are going to be around for a very long time to come.”