DNA evidence triples prosecution rates in criminal cases - study

DNA evidence is a potent tool, but it isn’t infallible; so its use in the legal system must be carefully considered.

 DNA, where genetics live. (Illustrative). (photo credit: PIXABAY)
DNA, where genetics live. (Illustrative).
(photo credit: PIXABAY)

In the pursuit of justice, law enforcement agencies depend heavily on forensic evidence, with DNA testing serving as the cornerstone of modern investigations. While the scientific and technological advancements in DNA testing have been extensively studied, there is little evidence about how the availability of DNA evidence influences prosecutors’ decisions to move cases forward.

Now, a study conducted by the Hebrew University of Jerusalem sheds light on the impact of DNA profiles on prosecutorial decisions in the criminal justice system. The study, titled “The role of DNA in criminal indictments in Israel,” was published in the Journal of Forensic Sciences. The research team included Esther Buchnik of HU’s Institute of Criminology; HU profs. Avi Domb and Nir Treves; Dr. Ron Gafny of the Israel Police’s Division of Identification and Forensic Science; and Prof. Barak Ariel of the Institute of Criminology at the University of Cambridge in the UK.

Legal scholars have long observed that the “queen of evidence” in police investigations is the confession. The criminal justice system broadly consented to this view, and when suspects admitted guilt, the case was substantially more likely to be prosecuted in a court of law, and the courts and juries in countries with a jury system were equally likely to convict based on a confession. The fundamental view was that the innocent do not take responsibility for crimes they did not commit. Therefore, a case in which a suspect confessed was usually a guarantee for a conviction.

The impetus for looking at wrongful convictions

It was not until the influential global Innocence Project that researchers got a closer look at the making of justice and the potential for wrongfully convicting people based on their confessions. To fill this knowledge gap, the researchers created a unique database by combining data from the Israel Police’s Forensics Division, which documented the presence or absence of almost 10,000 DNA profiles in criminal cases with data on each case’s subsequent indictment decision between 2008 and 2019.

This extensive dataset’s analysis yielded significant insights into the impact of DNA evidence on criminal prosecutions. The researchers discovered that 15% of all criminal cases presented to the prosecutor’s office were ultimately prosecuted. In stark contrast, the criminal justice system advanced 55% of cases with DNA profiles, showing the significant influence DNA evidence has on prosecutors’ decisions.

 Israelis walking in front of the entrance to the Hebrew University of Jerusalem (credit: MARC ISRAEL SELLEM/THE JERUSALEM POST)
Israelis walking in front of the entrance to the Hebrew University of Jerusalem (credit: MARC ISRAEL SELLEM/THE JERUSALEM POST)

The findings highlight the importance of using a scientific approach to prosecute offenders and recognize the value DNA evidence brings to the criminal justice system – but the researchers caution against the indiscriminate use of DNA evidence and emphasize the necessity of prudence. DNA evidence is a potent tool, they said, but it isn’t infallible; so its use in the legal system must be carefully considered. The study encourages a balanced approach that harnesses the benefits of DNA evidence while acknowledging its limitations.

This research contributes to the ongoing dialogue surrounding the role of forensic evidence in criminal investigations, specifically highlighting the impact of DNA profiles on prosecution decisions in Israel. The findings have implications for law enforcement agencies, legal professionals, and policymakers involved in the pursuit of justice.