This poster presents the successful resolution of a homicide case more than two decades after the crime, highlighting the impact of advanced forensic DNA analysis in cold case investigations. In 1989, an 80-year-old woman was found murdered in her apartment. She was lying in her living room with bare lower body and pieces of clothes wrapped around her head. The cause of death was determined to be a combination of strangulation and blunt force trauma. The victim was raped and semen could be detected in the vaginal swabs. Despite extensive investigations at the time, including the interrogation of more than 40 potential suspects, no perpetrator could be identified.

A first reinvestigation in 1999 was unsuccessful due to missing biological evidence. The vaginal swabs were no longer findable and the further investigation of the presence of sperm on the garments was negative.  In 2013, the case was reopened again, motivated by significant advancement in forensic methodologies. After the public prosecutor's office was initially opposed to another investigation due to a lack of prospects for success, it could be persuaded that currently much better investigation methods are available than during the previous investigations. A detailed re-evaluation of crime scene photographs led to the identification of new potential trace carriers. Subsequently, 38 samples were collected and analysed. Mixed DNA profiles containing genetic material from the victim and two unknown male contributors were detected in five samples.

Comparison of these mixed DNA profiles with the Austrian national DNA database in 2014 resulted in a match for one of the male contributors. The individual identified was a previously convicted offender, 20 years old at the time of the crime, who had not been considered during earlier investigations and had no known connection to the victim. He has just served a 4-year prison sentence for rape and was due to be released a few days later. Upon confrontation with the DNA evidence, the suspect confessed to the crime, stating that it had been a spontaneous act committed under the influence of drugs.

In 2015, the offender was convicted and sentenced to a long prison term. Additionally, he was classified as a high-risk, mentally abnormal offender with a significant likelihood of reoffending. This case demonstrates that even decades-old investigations can yield decisive results through the reanalysis of preserved evidence. Without the DNA database match, identification and conviction of the perpetrator would not have been possible.

Authors

• Ines Grießner (Department of Legal Medicine, University of Salzburg, Austria)
• Jan Cemper-Kiesslich (Department of Legal Medicine, University of Salzburg, Austria)
• Bettina Dunkelmann (Department of Legal Medicine, University of Salzburg, Austria)
• Gabriele Kreindl (Department of Legal Medicine, University of Salzburg, Austria)
• Eva Müller (Department of Legal Medicine, University of Salzburg, Austria)
• Waltraud Zahrer (Department of Legal Medicine, University of Salzburg, Austria)
• Franz Neuhuber (Department of Legal Medicine, University of Salzburg, Austria)