As part of the National Institute of Justice's (NIJ's) Just Science podcast series on case studies involving forensic science, this is an online audio of an interview with Dr. Jan De Kinder regarding how trace evidence became a critical piece of evidence in the murder of two young girls 20 years ago in Belgium.
Dr. Jan De Kinder is with the National Institute of Forensic Science and Criminology in the Belgium Department of Justice. At the time of the murders of the two girls, ages 7 and 10, Belgium was experiencing a large number of cases of missing children. In the case at issue in the interview, people interviewed in the girls' neighborhood had seen the girls talking with a man who lived nearby, and they directed police to his house. A search of the house led to a focus on some jeans soaking in a sink filled with water. This raised some suspicion, since the man typically washed his laundry at a public laundry. Subsequently, the girls' bodies were found in a concrete drainage ditch in shallow, flowing water. The procedure for obtaining trace evidence from the clothing of the girls and the suspect's pants is described in the interview. No DNA was found on either the girls or the jeans. Despite being exposed to water, however, fiber particles were obtained from the jeans and from the seams of the girls' clothing. Analysis found a match between distinctive elements of the fibers that were found in amounts to indicate transfer through more than incidental contact.