Establishing networks in a forensic DNA database to gain operational and strategic intelligence

Forensic DNA expertise is conventionally used to link, within a criminal case, a genetic profile found on a crime scene to the genetic profile of a known individual (for example, a suspect). DNA databases extend that logic across cases. By storing genetic profiles from different cases in such a database we can link cases that concern the same genetic profile (that is, the same individual) with each other. Although these are the two main approaches to exploiting forensic DNA, more forensic intelligence can be derived from databases containing genetic profiles. In this study, we explore the idea that different individuals can be linked to each other because their genetic profiles have been found on the same crime scenes, hereby forming DNA-based networks of individuals. To demonstrate that idea, data from the National DNA database of Belgium is analysed. The findings concern more than 400 networks, characterized in terms of size, geographical locations and types of crime. The potential of this forensic intelligence to support the Belgian judicial authorities and law enforcement in their missions is discussed.