By studying cases where individuals have been exonerated, we have been able to identify the main factors that contribute to wrongful convictions. At KWIP, we see these factors—often in combination—in the many applications that arrive in our mailbox from prisoners seeking our help.
The leading factors in wrongful convictions are:
- Eyewitness misidentification
- False confessions
- Police and prosecutorial misconduct
- Flawed forensic evidence
- Perjured testimony
Eyewitness misidentification is one of the most common factors in cases of wrongful conviction. Nationally, 28% of all exonerations involve mistaken eyewitness identification.
Social science research demonstrates that human memory is highly imperfect and fragile. When people experience a stressful event like a crime, they are much less able to make an accurate identification. Witnesses are even less accurate when they attempt to identify someone of another race. Additionally, lineups and photo arrays can be suggestive and lead a witness to pick the wrong person. This can happen when the suspect is the only person in an array who closely matches the description of the offender. Police officers can also influence the process by how they interact with a witness during the identification procedure. A police officer's comments, body language, and positive feedback can steer the witness towards a particular suspect and then inflate the witness's confidence in their identification.
Despite study after study proving the unreliability of eyewitness identification, it is extremely persuasive evidence. When a crime victim points to the defendant in the courtroom and says with certainty, "That is the person who did this to me," juries are unlikely to reject that testimony.
Kirk Bloodsworth (Maryland): Kirk Bloodworth, a former Marine, was convicted of the 1984 rape and murder of a nine-year-old girl in Maryland. At the time of trial, the case against Bloodworth seemed overwhelming, and the jury sentenced him to death. Five eyewitnesses all testified that they saw Bloodsworth with the victim around the time of her disappearance. Eight years later, DNA evidence proved that all five eyewitnesses were wrong. DNA testing of the victim's underwear and clothing showed that another man, Kimberly Shaw Ruffner, was the real perpetrator.
False confessions have been a factor in 12% of proven wrongful convictions nationwide. While it may seem difficult to understand why someone would confess to a crime they did not commit, there are many reasons that this can happen. For instance, physical intimidation or threats of violence by law enforcement can lead a suspect to falsely confess. Common interrogation techniques can also be psychologically coercive. For example, police are allowed to lie about the evidence and make a suspect believe that forensic testing or other conclusive evidence has already proven their guilt, even when this is not true. Police might also provide false assurances that things will go better -- and a long interrogation will finally cease -- only if the person confesses. The truth is that many people break under this pressure, especially when the interrogation is lengthy or when they've been deprived of food, water, and/or sleep. Young people and people with intellectual disabilities are especially vulnerable to giving a false confession.
Lorenzo Montoya (Colorado): Lorenzo Montoya was wrongfully convicted in 2000 for participating in the robbery and murder of a special education teacher. Though he was just 14 years old, he was tried as an adult and sentenced to life in prison without the possibility of parole. His conviction rested in part on a false confession. His mother was present during the first 40 minutes of the police interrogation. After she left, detectives aggressively interrogated Montoya by shouting, pounding on the table, and telling him that he was going to be sentenced to life without parole. Despite denying his involvement in the murder over 60 times, Montoya finally gave in to the pressure and falsely confessed. There were, however, clear factual errors in his confession. When police pressed Montoya, he fixed the errors in his statement so that it squared with the official narrative of the crime. After serving 14 years in prison, Montoya was exonerated by DNA.
Police and Prosecutorial Misconduct
Official misconduct by police officers, prosecutors, or other government officials has been present in 54% of wrongful convictions across the nation. Because criminal cases have many different stages, official misconduct can occur in numerous ways. At the investigation stage, police engage in misconduct when they deliberately use suggestion in an identification procedure, coerce a witness to implicate a suspect, fabricate physical evidence, or use improper interrogation techniques to secure a confession. At the trial stage, prosecutors corrupt the process when they conceal exculpatory evidence (i.e., evidence favorable to the defendant) or when they introduce false or perjured testimony.
Timothy Masters (Colorado): In 1999, Timothy Masters was tried and convicted of a brutal murder that had taken place twelve years earlier. The female victim was stabbed in the back and sexually mutilated. At trial, the prosecution's case rested heavily on the testimony of a psychologist, J. Reid Meloy, who examined writings and drawings created by Masters as a teenager following the death of his mother. The psychologist insisted that this material reflected a displaced anger towards women and directly implicated Masters in the crime. What Masters did not know at trial -- because the prosecution concealed the evidence -- is that police had consulted with two other experts who forcefully disagreed with Dr. Meloy's conclusions. Prosecutors also suppressed evidence about an alternate suspect who had a history of sexual deviancy, lived 100 yards from the murder scene, and committed suicide following his arrest for a separate sex crime. Unable to defend himself with this exculpatory evidence, Masters was convicted and sentenced to life in prison. He served nine years in prison before he was exonerated by DNA.
False and/or Misleading Forensic Evidence
False or misleading forensic evidence has been a contributing factor in 24% of exoneration cases across the country. Most forensic disciplines were developed within law enforcement and have not been subject to the kind of rigorous testing normally conducted to validate a scientific theory. As the forensic sciences have come under greater scrutiny, some disciplines -- including bitemark analysis and microscopic hair comparison -- have been exposed as nothing more than junk science. Even in more reliable disciplines, experts often overstate their results and fail to acknowledge the limitations or error rate of a particular forensic technique. Finally, like everyone, forensic practitioners can make mistakes, including mixing up samples or contaminating specimens. In some cases, forensic analysts have fabricated results, hidden exculpatory evidence, or reported results when testing had not been conducted.
Krystal Voss (Colorado): In 2004, Krystal Voss was convicted of child abuse resulting in death after her 17-month-old son, Kyran, died from a head injury. From the beginning, both Voss and the child's babysitter told the same story: Kyran fell backwards off the babysitter's shoulders and hit the frozen ground on his head. Medical personnel at the hospital rushed to the conclusion that Kyran was instead the victim of child abuse. Under a theory of Shaken Baby Syndrome (SBS), prevalent at that time, violent shaking by an adult is the only explanation when a child, like Kyran, presents with a triad of symptoms: brain swelling, brain hemorrhaging, and retinal hemorrhaging. Proponents of SBS have also insisted that short falls cannot cause this constellation of symptoms. Voss was convicted under the SBS theory and was sentenced to 20 years in prison. In the appeals process, Voss's new attorney presented compelling new medical evidence demonstrating that (1) short falls can cause the triad of symptoms associated with SBS; and (2) Kyran had bruising on one side of his head consistent with a fall onto the frozen ground. Voss's conviction was overturned and she was released from prison after serving 13 years.
False accusation or perjury is the most common feature of wrongful convictions and has been a factor in 60% of documented exonerations. Most often, witnesses lie because they receive some benefit for testifying against the defendant. For example, a person in jail facing criminal charges can secure a favorable plea bargain, dismissal of their own charges, special privileges in jail, or even money by offering damning evidence against a fellow inmate. These benefits create a strong incentive to lie. In many wrongful convictions, defendants were not given key information related to the credibility of the incentivized witnesses who testified against them, including the exact benefits received, the witness's history of cooperating in other cases, and the witness's criminal history.
DeShawn Jones (Colorado): In 2011, a woman reported that she was sexually assaulted by two men. The woman was taken to a nearby hospital where a forensic medical exam was conducted. DNA testing of a vaginal swab from that exam identified DeShawn Jones, and he was arrested. Though Jones told his lawyer that he and his uncle had had consensual sex with the alleged victim in exchange for drugs, the lawyer failed to interview key witnesses or hire an investigator. Facing the prospect a long prison sentence, Jones decided to accept the state's offer to plead to a lesser charge and receive probation. But, his probation was revoked, and he landed in prison, when he refused to admit his guilt during mandatory sex offender treatment. Two years into his prison sentence, the alleged victim admitted that she had lied about the sexual assault. When interviewed by Jones' appellate attorney, she admitted to having consensual sex with Jones and his uncle. She fabricated the story of sexual assault because she had missed her curfew at the shelter where she was staying and did not want to be kicked out. Following a reinvestigation of the case, the district attorney's office concluded that Jones' conviction should be vacated.
- Innocence Project, How Eyewitness Misidentification Can Send Innocent People to Prison
- The National Registry of Exonerations, Lorenzo Montoya
- The National Registry of Exonerations, Timothy Masters
- Innocence Project, Overturning Wrongful Convictions Involving Misapplied Forensics
- UC Irvine, Government misconduct cause of most wrongful convictions
- Innocence Project, Forensic Science: Problems and Solutions
- The National Registry of Exonerations, Krystal Voss
- The National Registry of Exonerations, Exonerations by Contributing Factor
- The National Registry of Exonerations, DeShawn Jones
- Washington Innocence Project, Causes of Wrongful Conviction