Expert explains how new DNA technology could advance LaDonna Cooper investigation

The 1987 homicide case of Ladonna L. Cooper, a 32-year-old mother of three, is being revisited with new DNA technology nearly 40 years after her death. Williamson County authorities recently exhumed Cooper’s remains as part of a renewed investigation into her killing, which occurred after she disappeared from a restaurant on Coolidge Street in Marion, Illinois, in March 1987. Her body was found the following day. Trish Oberweis, a criminal justice studies professor at Southern Illinois University Edwardsville, highlights how DNA analysis has evolved since the 1980s, when forensic genetics were in their infancy. Modern techniques, including forensic investigative genetic genealogy—used in cases like the Golden State Killer—can now identify potential suspects by matching DNA profiles to family trees, narrowing the focus for further investigation. Oberweis notes that developing a genetic profile often requires multiple attempts, as samples may degrade or fail initial testing. She emphasizes that while DNA evidence is critical, supporting details like witness statements, timelines, and investigative records remain essential, especially in a case as old as Cooper’s, where witnesses may no longer be available. Investigators remain hopeful that advances in forensic science will provide answers for Cooper’s family, though the process may take time. The renewed effort follows decades of stagnation, with authorities now leveraging both genetic genealogy and traditional fingerprinting methods to confirm potential leads. Oberweis stresses that homicide cases from four decades ago face unique challenges, including faded witness memories and lost evidence. Despite these hurdles, the combination of new technology and family-driven interest has reignited efforts to solve Cooper’s murder.