A brief history of junk science and bad forensics

John and Sally Sweek, a young married couple living in east Dallas, were known by friends—a lively party crowd—to sell cocaine out of their apartment. Two of those friends found their bodies there in 1987: Sweeks had been stabbed to death.

The bloody crime scene was littered with what investigators considered excellent forensic evidence. John appeared to have a bite mark on his left forearm. Sally had hair under her fingernails, apparently from fighting her attacker. There were two pairs of bloody shoe prints.

Police first suspected a gang member, then a tip led them to Steven Mark Chaney, a friend who owed Sweeks $500. It turned out that the couple often sold drugs to friends on credit.

Years later, Chaney became attorney M. Chris Fabricant’s first client at the Innocence Project.

Fabricant, now the nonprofit’s Director of Strategic Affairs, quickly learned that Chaney had an alibi corroborated by multiple witnesses. His conviction rested on what Fabricant saw as flawed evidence — nuggets of forensic gold in the 1980s that turned out to be worthless junk in the decades that followed. A shoe print appeared to match a pair owned by Chaney. And the chief dental consultant for the Dallas Medical Examiner had visited Chaney in jail, examined his teeth and determined that Chaney could not be ruled out as the person who made the bite mark.

But in the 2010s, bite marks and shoe prints were considered junk science. Another seemingly strong piece of evidence against Chaney, a latent fingerprint, confirmed that Chaney had visited the apartment, but that could easily be explained away: He had partied with the Sweeks before their deaths.

Fabricant’s new book, Junk Science and the American Criminal Justice System (published by Akashic Books in April) tells Chaney’s story and those of other innocent people convicted on flimsy forensic evidence. Chaney was released in 2015 – after nearly 30 years in prison.

Fabricant expertly delves into now-discredited forensic tactics, including bite mark analysis and antiquated methods used in arson investigations, to show how investigators and prosecutors often used pseudoscience to imprison innocent people for decades all. It profiles several key Texas figures, including the infamous Dallas County District Attorney Henry Wade, whose ultra-high conviction rate defined his career and led to numerous wrongful convictions.

of Texas Observer spoke with Fabricant about his mission to “change the narrative about forensic infallibility,” as well as Texas’ place in the national discourse about junk science and the ongoing fight to keep it out of courtrooms.

This interview has been edited for clarity and length.

Your first case with the Innocence Project was in Texas. What were the things you had to contend with that were specific to the state?

Texas is the most paradoxical state for litigating forensic science in the country. There is a long and scandalous history of using junk science… There are examples of botched executions involving Cameron Todd Willingham, Tommy Lee Walker and David Wayne Spence, all of which relied at least in part on junk science. At the same time, Texas has some of the most progressive laws [regarding post-conviction innocence claims] and some of the most innovative District Attorney’s offices in the country as well. There is an interesting story from the Dallas District Attorney’s Office in particular, where my client Steven Mark Chaney was wrongly convicted of murder and spent decades in prison for a crime he did not commit.

Texas has a long history of using unreliable evidence. [It also has made] unique efforts to address that sobering history, including passage of the nation’s first junk science write-up, the Dallas District Attorney’s Office’s first sentencing integrity unit … And the Texas Forensic Science Commission, which is the most important, innovative and transparent forensic science commissions in the country, if not in the world.

Dallas has become a poster child for overturning convictions, many of which were passed during Henry Wade’s tenure as DA from 1951 to 1987. Wade is best known as the prosecutor in Roe v. Wade. But what does his career tell us about Texas’ historical attitude toward forensics?

Everything you need to know about the criminal justice system in Texas can be learned by studying the history of the Dallas County District Attorney’s Office. In fact, everything you really need to know about our justice system and the country as a whole.

You start by using our criminal justice system to enforce Jim Crow laws and moving from Jim Crow to mass incarceration policies to control marginalized communities. This was directed at so-called “tough on crime” stores such as Henry Wade’s. History shows that this led to the wrongful prosecutions and executions of innocent and disproportionately large and black and brown people.

As we see some progress made in this area, Craig Watkins [one of Texas’ first Black elected DAs] brings to this incredible period the change that was truly responsible for unraveling the legacy of Henry Wade and his evidence preservation policies.

When you have indisputably wrongful convictions, and what I argue are wrongful executions, it really forced Texas and Dallas in particular to take a hard look at what we’re doing in our criminal courts and try to take some action. prophylactic to avoid this. again: things like the Michael Morton Act, and some retrospective measures including junk science writing. The Forensic Science Commission is important both in terms of past cases … but also in preventing future crime lab scandals and ensuring, as far as possible, that valid and reliable science is being used in Texas criminal courts.

“Everything you need to know about the criminal justice system in Texas can be learned by studying the history of the Dallas County District Attorney’s Office.”

Several well-known forensic doctors have been discredited in recent years. Your book even points out some problems with fingerprints, which are often imperfect in a crime setting. Can we trust anything but the DNA test?

I’ve been asked this question a fair amount, and it’s hard to answer categorically. If I were to answer categorically, my answer would be no.

But to be a little more specific… you can use a reliable technique and make it pretty unreliable, depending on the quality of the evidence. If you don’t have enough information from a crime scene sample – and we don’t really have any objective threshold for how much information a person needs to reach a reliable conclusion – then we can take a reliable technique and make it quite harmful. We see that in fingerprinting, when we don’t have high-quality latent fingerprints, it’s much more susceptible to cognitive bias, it’s much more likely to have potential random matches, and it’s much more likely to have a degree of higher the error. This is true to some extent with DNA evidence as well. Then there are things like bite marks, which can never be reliably done under any circumstances.

That’s why it’s so important that courts take seriously not only their role in ruling out junk science—things like microscopic hair comparison evidence, bite mark analysis, tire treads, and cases of Down syndrome. Baby Trembling – but also take seriously their role in ruling out an unreliable issue. the application of an otherwise reliable technique that we see very, very often. And this is as common as any other kind of junk science.

Your book notes that for most crimes, DNA exonerations are not an option. Crimes such as robberies, arsons, drive-by shootings, or even assaults often do not involve the transfer of any genetic material. Even in Steven Chaney’s case, the DNA under the victim’s fingernails was found to belong to someone else, but that wasn’t enough to convince the courts – they assumed he’d just had an accomplice. Is there a solution for wrongfully convicted people sitting in prison with no hope of a DNA exoneration?

One of the reasons I focused on Steven Chaney’s case is that it really shows that even with some DNA evidence what a Herculean struggle it is to overturn a conviction—let alone demonstrate innocence without the power of forensic DNA analysis. legal. And it becomes increasingly difficult each time the Supreme Court reinterprets the Anti-Terrorism and Effective Death Penalty Act to further extinguish avenues of post-conviction review of state court convictions, where the vast majority of wrongful convictions occur.

We’re often in a war against time, and we’re also often in this frustrating position of scientific reality that has defied legal precedents but is not accepted in criminal courts… I think the continued use of junk science and other unreliable techniques forensics, is whistling by graveyards or creating clients for the Innocence Project and making it increasingly difficult to exonerate the innocent.

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