The Relationship between DNA and Non-Biological Evidence in Sexual Assault Cases

• In Event: Research on Sexual Assault Medical Forensic Examinations and Criminal Justice System Outcomes

Abstract

The potential of DNA testing in sexual assault cases has gained increasing attention from practitioners, advocates and researchers, but the role of DNA and other evidence in the prosecution of sexual assault cases is not well understood. Little is known about the frequency of different types of evidence and how DNA evidence is related to non-biological forms of evidence. This presentation will explore the frequency of different types of evidence in 257 cases of adult and adolescent sexual assault incidents referred to an urban district attorney’s office from 2005 to 2011, and include data from interviews with assistant district attorneys detailing use of DNA in sexual assault cases. DNA matches to suspect were obtained in a small minority of cases. Cases with DNA matches were significantly more likely to have other physical evidence at the crime scene, witnesses that corroborated the victim’s account, fingerprint evidence, and more substantial evidence in general. Interviews indicate that prosecutors see DNA matches as valuable in every case as part of an array of evidence, but seldom think that DNA alone determines case outcomes. The presentation will discuss implications for enhancing the criminal justice response to sexual assault.

Authors

• Laura Siller, Northeastern University

• Ted Cross, University of Illinois at Urbana–Champaign

• Maja Vlajnic, Northeastern University

• Alex Wagner, Fisher College

• Megan Alderden, Illinois Criminal Justice Authority