Miscarriages of Justice: Law Enforcement and the Resistance of Science

The resistance by many police departments and prosecutors to adopt the best practices in forensic testing has resulted in miscarriages of justice.

| October 2012

  • Failed Evidence
    "Failed Evidence," by David A. Harris, explores the real reasons that police and prosecutors resist scientific change, and it lays out a concrete plan to bring law enforcement into the scientific present.
    Cover Courtesy NYU Press

  • Failed Evidence

Written in a crisp and engaging style, free of legal and scientific jargon, Failed Evidence (NYU Press, 2012), by David A. Harris, will explain to police and prosecutors, as well as anyone else who cares about how law enforcement does its job, why the criminal justice system has resisted science for so long and where we should go from here. Because only if we understand why law enforcement resists the best that science has to offer will we be able to convince those in power to adopt it. In this excerpt from the introduction, Harris tells of certain miscarriages of justice wherein traditional investigative methods failed to place blame on the guilty and, in turn, punished the innocent.  

Science-Driven Policing, or Police Indifference to Science?

In 2010, and for the previous nine years running, CSI: Crime Scene Investigation ranked among the most popular shows on television in the United States. The program became a hit so quickly after its premiere in 2000 that the original series, set in Las Vegas, spawned two clones: CSI: Miami and CSI: New York. These shows put a new twist on the old police procedural drama. The CSI officers solved crimes with high-tech forensics: gathering DNA, lifting fingerprints with revolutionary new techniques, and using science to reconstruct the paths of bullets. Watching these programs, the viewer knows that policing has changed. For every member of the CSI team using a gun, more wield test tubes, DNA sampling equipment, and all manner of futuristic gizmos designed to track down witnesses and catch the bad guys.The show signals a break with the past, because it revolves around the way police use modern science to find the guilty and bring them to justice. 

CSI reflects the emergence of DNA evidence as a powerful tool since it first appeared in American criminal courts in the late 1980s. With DNA and other formidable forensic techniques on our side, little could escape our scientific police work. In this new world, in which science could tell us definitively that the police had the right guy, with a probability of millions or even billions to one, the game had changed for good. The “just the facts, ma’am” approach of Sergeant Joe Friday, and the slow and inexact old-school ways that might or might not turn up evidence, began to seem like quaint relics of a bygone era. Sure, some real-world police protested that CSI raised unrealistic public expectations of both forensic science and the police, but CSI simply put a drama-worthy sheen on the way that police departments liked to portray themselves in the age of DNA: using the best of what science had to offer to construct air-tight criminal cases. Police frequently announced that they had used DNA to catch guilty people, sometimes for crimes far in the past, attracting wide public notice and bolstering law enforcement’s science-based image. With headlines like “State, City Police Laud Increase in Arrests Using DNA” in Baltimore, “Georgia DNA Solves 1,500 Cases” in Atlanta, “DNA Databanks Allow Police to Solve at Least Four Murders” in Memphis, and “With Added Lab Staff, DNA Tests Resolve String of Old Killings” in Milwaukee, the direction and approach of police work now seem woven together with the latest scientific advancements. Science has given police and prosecutors an enormous, unbeatable advantage.

But this all-too-common view of modern police work using science to move into a gleaming, high-tech future turns out to be a myth. When we strip away the veneer of television drama and the news stories about how DNA has helped police catch another killer or rapist, the real picture concerning law enforcement and science actually looks much different. With the exception of DNA (and then, only sometimes), most of our police and prosecutorial agencies do not welcome the findings of science; they do not rush to incorporate the latest scientific advances into their work. On the contrary, most police departments and prosecutor’s offices resist what science has to say about how police investigate crimes. The best, most rigorous scientific findings do not form the foundation for the way most police departments collect evidence, the way they test it, or the way they draw conclusions from it. Similarly, most prosecutors have not insisted upon evidence collected by methods that comply with the latest scientific findings in order to assure that they have the most accurate evidence to use in court. Like police, most prosecutors have resisted. And this resistance comes despite a nearly twenty year drumbeat of exonerations: people wrongly convicted based on standard police practices, but proven irrefutably innocent based on DNA evidence. These DNA exonerations, now numbering more than 250 nationwide, prove that traditional techniques of eyewitness identification, suspect interrogation, and forensic testing contain fundamental flaws that have resulted in miscarriages of justice.



Yet the resistance continues. At best, police and prosecutors have used advances in science selectively, when it helps their cases. At worst, they have actively opposed replacing questionable investigative methods with better, empirically proven techniques, sometimes even insisting on retaining flawed methods. As a matter of principle and logic, this indifference to improved practices that will avoid miscarriages of justice seems puzzling and irresponsible, since we know for certain that we can do better than we used to. As a matter of concrete cases, when we see that the failure to use our best methods sometimes leads to both the punishment of the innocent and the escape of the guilty, indifference can become a catastrophe for our system of justice. It is this resistance to sound, science-based police investigative methods that forms the heart of this book.

Brandon Mayfield and the Infallible Science of Fingerprinting

Brandon Mayfield’s case makes a striking example. In March of 2004, terrorists bombed four commuter trains in Madrid, killing 191 people and wounding approximately eighteen hundred. Spanish police soon found a partial fingerprint on a plastic bag in a car containing materials from the attack. Using a digital copy of the fingerprint sent by the Spanish police, a senior FBI fingerprint examiner made “a 100% identification” of Brandon Mayfield, an Oregon attorney, whose prints appeared in government databases because of his military service and an arrest years earlier. Three other fingerprint experts confirmed the match of Mayfield to the print found on the bag: FBI supervisory fingerprint specialist Michael Wieners, who headed the FBI’s Latent Print Unit; examiner John Massey, a retired FBI fingerprint specialist with thirty years of experience; and Kenneth Moses, a leading independent fingerprint examiner. The FBI arrested Mayfield and at the Bureau’s request incarcerated him for two weeks, despite the fact that he did not have a valid passport on which he could have traveled to Spain; he claimed he had not left the United States in ten years. When the FBI showed the Spanish police the match between the latent print from the bag and Mayfield’s prints, the Spanish police expressed grave doubts. The FBI refused to back down, even declining the request of the Spanish police to come to Madrid and examine the original print. Only when the Spanish authorities matched the print with an Algerian man living in Spain did the FBI admit its mistake, releasing Mayfield. The Bureau issued an apology to Mayfield—an action almost unprecedented in the history of the FBI—and later paid him millions of dollars in damages in an out-of-court settlement.