The Limits of DNA Evidence in Innocence Cases

Death row prisoners with credible evidence of their innocence have garnered widespread attention this month with the execution of Marcellus Williams in Missouri, the near-execution of Robert Roberson in Texas and arguments before the U.S. Supreme Court Glossip vs. Oklahoma. There is a common misconception that DNA evidence is widely available in all cases and is central to exoneration. In reality, however, DNA exonerations in death sentence cases are relatively rare. DPI has identified 34 cases of people released from death row with DNA evidence in 15 states in the modern death penalty era – the first case was Kirk Bloodsworth in 1993 (he was convicted in 1985). These numbers represent only 17% of the 200 releases from death row.

The average time people exonerated thanks to DNA spend on death row is 18.6 years, which in the 24 cases means a total of 631 years in prison for crimes they didn't commit. Few of those exonerated were adequately compensated.

The Innocence Project reports 375 DNA exonerations in criminal cases between 1989 and 2020. Before 2000, only a handful of states allowed DNA testing after a conviction. That changed in 2004 with the passage of the Justice for All Act. In her Article 2020, Chi-Hsin Engelhart argued that post-conviction DNA testing is a procedural right that should be constitutionally protected. She notes that these protections are particularly important in the death row context to examine the potential for wrongful execution and concludes that denial of access and testing could result in a violation of the Eighth Amendment. Ms. Engelhart argues that courts should shift their focus from finality to the accuracy of the legal system and that allowing DNA testing in post-conviction proceedings would advance that goal.

During a recent discussion moderated by DPI Executive Director Robin Maher at the French Ambassador's residence in Washington, DC, Vanessa said PotkinDirector of Special Procedures at the Innocence Project noted that DNA evidence is available for fewer than 10% of crimes. The case of Marcellus “Khaliifah” Williamswho was executed on September 24, 2024, makes it clear that DNA evidence can also be obtained from the crime Crime scene, forensic Materials can deteriorate or become contaminated, rendering them useless in proving a defendant's innocence.

Robert DuBoise was wrongly convicted of murder in Florida in 1983 and sentenced to death based on flawed forensic investigations, including the now-debunked practice of bite mark detection. A DNA test finally exonerated him in 2020 and in February 2024 Mr DuBoise received $14 million in compensation for his wrongful conviction.

As scientific and technological advances continue to advance, many prisoners could benefit from these advances. However, many legal procedural barriers continue to prevent prisoners from accessing DNA evidence that has the potential to exonerate them.