Yesterday a story was aired on public radio and TV about an investigation launched by NPR News Investigations, ProPublica and PBS Frontline, which analyzed nearly two dozen cases in which people have been accused of killing children based on flawed work by forensic pathologists. The story highlighted the use of so-called “Junk Science” by unethical (and, in my opinion, criminal) prosecutors to secure the convictions, imprisonment, and even executions of innocent people.
Because we are seeing the use of flawed and fraudulent forensic “evidence” in the cases of both Jordan Brown and James Prindle, it may be useful for us to explore today the broader context of the role forensics plays in American injustice.
Even before the television show CSI became so popular, juries and judges have tended to believe what “scientific experts” say in criminal cases. While scientific evidence can be a tremendously beneficial crime-solving tool, the use of inaccurate and fraudulent junk science has plagued our criminal justice system for years.
Junk science takes the form of false autopsies, inaccurate evaluations of hair and fiber evidence, dog scent lineups, grossly misleading reports and testimony by corrupt, incompetent or shoddy crime labs, and the use of disproven arson investigation techniques.
In 2009 Texas Governor Rick Perry was involved in the wrongful execution of Todd Willingham, a man accused of burning down his house with his three small children inside. By the time of Willingham’s execution, it had been established that Willingham had been wrongfully convicted based on junk science evidence and testimony, but Perry allowed the execution to proceed. If Perry decides to take a run at the Presidency in 2012 (as seems likely), the issue of junk science in the Willingham case will likely achieve national prominence as Perry’s role in the state murder of an innocent man is examined. Many Texans seem to take bloodthirsty delight in their executions, but Perry is likely to receive harsh criticism outside of Texas for sacrificing an innocent man to his selfish political ambitions.
Yet junk science is not just a Texas problem. There are politically ambitious prosecutors everywhere in America who regularly take advantage of the gullibility of jurors and the willingness of courts to allow the use of junk science to railroad the innocent. In case after case, prosecutors have used phony “experts” with little or no training or education, false information from labs, and dubious theories with no basis in fact to get convictions.
The use of such “evidence” is not limited to the courtroom: as we have seen in the Jordan Brown persecution, law enforcement agencies have come more and more to rely on fraudulent evidence and interpretation in making arrests and getting indictments.
Our adversarial, dog-eat-dog criminal justice system in practice places a higher value on prosecutors winning at all costs than discovering the truth. In such a system, dishonest and lazy prosecutors find the use of junk science an irresistible temptation.
In his 2006 book Junk Science, Dan Agin says the two main causes of resulting wrongful convictions are fraud and ignorance.
Fraud
Too often, forensic analysts’ testimony goes further than the science allows. Many forensic techniques that have been practiced for years—but not subjected to the rigors of scientific research—are accepted and repeated as fact. Juries are left with the impression that the evidence is more scientific than it is, and the potential for wrongful convictions thus increases.
However, improper forensic testimony is not limited to unvalidated disciplines. For example, among DNA exoneration cases pursued by various Innocence Projects all over the country, scores of people were found to have been wrongfully convicted after forensic testimony misrepresented serology (blood testing) results. In some cases, analysts failed to disclose that a biological sample could be a mixture of fluids from the victim and perpetrator, and that the victim’s blood type could mask the perpetrator’s—thus making it impossible to know the perpetrator’s blood type. In other cases, expert witnesses have provided inaccurate statistics for the percentage of the population that shares the perpetrator’s blood type.
In many cases, the science—rather than the scientist—is inadequate. In other cases, forensic analysts make mistakes that could result from lack of training, poor support or insufficient resources. But in many cases, forensic analysts have engaged in outright lying.
For example, in some wrongful convictions later overturned with DNA testing, forensic analysts fabricated test results, reported results when no tests were conducted, or concealed parts of test results that were favorable to defendants. In virtually all of these cases, analysts had engaged in misconduct that led to multiple separate wrongful convictions, sometimes in multiple states.
This chart summarizes the analysis of the types of misconduct in 74 wrongful conviction cases the national Innocence Project has overturned:

The Innocence Project has uncovered forensic misconduct by scientists, expert witnesses, and prosecutors that leads to wrongful convictions in many states. The following are among the more notorious:
• A former director of the West Virginia state crime lab, Fred Zain, testified for the prosecution in 12 states over his career, including dozens of cases in West Virginia and Texas. DNA exonerations and new evidence in other cases have shown that Zain fabricated results, lied on the stand about results, and willfully omitted exculpatory evidence from his reports.
• Pamela Fish, a Chicago lab technician, testified for the prosecution about false matches and suspicious results in the trials of at least eight defendants who were convicted, then proven innocent years later by DNA testing.
• A two-year investigation of the Houston crime lab, completed in 2007, showed that evidence in that lab was mishandled and results were misreported.
Unvalidated or improper forensic science contributes to over 50% of the wrongful convictions which have been overturned with DNA testing. Yet while DNA exonerations provide a window onto the effects of unvalidated or improper forensic science in wrongful convictions, DNA does not solve the problem.
Experts estimate that only 5%-10% of all criminal cases involve biological evidence that can be subjected to DNA testing. In the other 90%-95% of crimes, DNA testing is not an option—so the criminal justice system relies on other kinds of evidence including forensic disciplines that may not be scientifically sound (like dog scent lineups or bite mark analysis), which lack accepted scientific standards or are improperly conducted.
Ignorance
Juries usually believe expert witnesses. Unfortunately, juries rarely understand the expert testimony they hear, and don’t know what weight—if any—to give to terms like “consistent with,” “matching,” and “virtually excluded.” Lawyers and judges rarely understand the science that is presented by these experts, either. When an expert falls short of the minimum standards of the profession, or worse, is an outright fraud, it can spell disaster for the wrongly accused.
Forensic analysts sometimes testify in cases without a proper scientific basis for their findings. Testimony about more dubious forensic disciplines (such as matching a defendant’s voice to a voicemail recording) is cloaked in science, but lacks even the most basic scientific standards.
Even within forensic disciplines that are more firmly grounded in science, evidence is often made to sound more precise than it should. For example, analysts will testify that hairs from a crime scene “match” or “are consistent with” defendants’ hair—but because scientific research on validity and reliability of hair analysis is lacking, they have no way of knowing how rare these similarities are nor how meaningful this evidence is.
In many cases forensic science is falsely presented to juries to be 100% reliable when it is not so. In many DNA exonerated cases, serologists failed to disclose the limited reliability of the test or misapplied statistical principles. In such cases, juries were misled by the testimony and innocent people were convicted. The use of DNA has proven that these tests are unreliable and frequently produce erroneous results. Juries are presented with the evidence that matches the prosecutor’s argument, but are not told that the evidence may not be accurate, exact, or up-to-date.
This morning, in connection to yesterday’s story about a Texas man wrongly accused and imprisoned for the shaking death and rape of a 6-month-old baby, public radio aired this interview with the pediatric neurosurgeon who originated the diagnosis of “Shaken Baby Syndrome” decades ago. He worries that the diagnosis is too often used by medical examiners and doctors without considering other possible causes for a child’s death or injury.
In this interview he says there are too many cases like one he recently reviewed in Arizona after a defense attorney asked him to look at the case of a father who has spent 10 years in prison after being convicted of killing his 5-month-old son by shaking him.
Listen to Dr. Norman Guthkelch being interviewed on NPR’s “Morning Edition”
A couple days ago in Minnesota where budget wrangling between the Governor and the Legislature threatens a state government shutdown, a judge ruled that the courts should continue operating even if most of the rest of government goes into hiatus. It seems to me that this ruling underscores my belief that honest justice is foundational to the legitimacy of all government.
As long as widespread abuses in our justice system are allowed to continue, as long as corrupt prosecutors and dishonest police are allowed to act with impunity and without fear of accountability or reprisal, government loses all moral authority to collect taxes or to demand citizens’ compliance with any of its laws.
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Groove of the Day
Listen to Thomas Dolby performing “She Blinded Me With Science”