These definitions explain the “Causes of Wrongful Prosecution” in the case search page.
This category includes cases where police or prosecutors engaged in misconduct such as withholding evidence, pressuring witnesses to give false testimony, or secretly compensating witnesses. Many defendants have been charged capitally despite evidence of their innocence, in an effort to secure their testimony against others involved in the crime.
While most state officials are honest, any system run by individuals will have instances of negligence or corruption. For police and prosecutors, the tremendous pressure to solve crimes and convict perpetrators can be a corrupting influence. Across the country, instances of misconduct have been uncovered in thousands of cases, many of which resulted in exonerations. Even if misconduct is present in only a tiny percentage of cases, it can have devastating consequences in capital prosecutions.
In many cases, investigators had little or no physical evidence and relied heavily on the statements of people likely to be untruthful, such as co-defendants, jailhouse informants, or people being compensated for their testimony. Some were pressured or intimidated into implicating suspects, such as a woman who was told she would be charged with murder and lose custody of her children if she did not falsely claim that she saw her boyfriend putting a body into a car trunk.
Even in cases where witnesses were not intimidated, there were often obvious reasons to doubt their credibility, such as the fact that they were receiving cash payments or reduced prison sentences in return for their statements. Yet, their statements were used to justify capital prosecutions and keep people in jail for years.
Tunnel vision is a well-established phenomenon in law-enforcement, in which investigators identify a suspect and then structure their investigation around proving that person’s guilt, rather than conducting an unbiased inquiry. Once a suspect is identified, police and prosecutors tend to favor information pointing to that person’s guilt and discard information that supports other theories.
Research shows that tunnel vision is a natural tendency rooted in human psychology, and that it can cause even well-intentioned investigators and prosecutors to make mistakes. There is clear evidence that tunnel vision has been a factor in wrongful convictions around the country. Yet, law enforcement and other state officials often fail to implement strategies to diminish the effect of tunnel vision, resulting in innocent people being targeted while the true perpetrators remain free.
In 2010, the N.C. State Bureau of Investigation, which provides forensic evidence for murder cases across the state, admitted that analysts in its crime lab had systematically withheld or distorted blood evidence to secure convictions in at least 230 cases, including 10 in which the defendants were sentenced to death. However, problems with forensic evidence go far beyond improper blood evidence. For decades, the policy and practice in the State Crime Lab was to seek results that helped prosecutors win cases and to suppress evidence that suggested a defendant’s innocence. This practice was at play in many of the cases documented here, while in other cases, law enforcement agencies relied on outdated or improper scientific techniques, including flawed arson science that led to the execution of an innocent man in Texas.
Under the law, a person acting in self defense cannot be guilty of first-degree capital murder. The United States has a long history of allowing people to protect themselves, even with lethal force, in cases where their lives are at risk. Despite this, our research finds that the state has repeatedly pursued the death penalty in cases where there is strong evidence of self defense. Many of these cases involve minority defendants.
The threat of the death penalty puts defendants at high risk of confessing to crimes they did not commit. These suspects plead guilty in order to avoid a capital trial, finding a lesser sentence preferable to the possibility of execution. The vast majority of those who confess are eventually convicted, despite strong evidence that false confessions are common. About one in five people exonerated by DNA in the United States have falsely incriminated themselves, usually during intense police interrogations. (One of them was Henry McCollum, North Carolina’s longest serving death row inmate.) False confessions are a particular problem among vulnerable groups such as teenagers and those with mental illness or disabilities.