Digital traces. Written communication from violent lone offenders

This report presents research carried out within the project that has been assigned to the Swedish Defence Research Agency by the Swedish Government (Ku2016/01373/D samt Ju2018/01298/KRIM). The topic of the report is violent lone offenders; individuals who without, or with minimal help from others, commit planned violent attacks. The report highlights some of the common factors that separate lone offenders from a general population. The existing research on lone offenders largely builds on information from medical or prison jounals and interviews with people who have lived close to them. To this, we add another dimension: Their own words. Several of the common psychological factors are expressed in the corpus of text that many lone offenders leave behind on social media. Based on research in psychology, linguistics and computer science, we have developed a tool for text analysis, aimed to assist professionals in risk assessment of potential lone offenders. The more we know about the complex interplay between factors that characterise lone offenders, the more likely we are to be able to prevent their attacks before it is too late.