In Sweden, between 1990 and 2013, a small proportion of homicides were committed by strangers, accounting for around 8–13% of the total number of incidents. A recent study has investigated the characteristics of these homicides, categorising them into “conventional” and “nonconventional” types based on their motives. The findings were published in the journal Medicine, Science and the Law.
The study divided stranger homicides into two main categories. Conventional stranger homicides were those that had a clear motive, such as spontaneous altercations, robberies or burglaries, and gangland conflicts. Nonconventional homicides, on the other hand, were distinguished by their uncommon motives, which included hate offences, politically motivated crimes, sexual offences, and acts linked to mental health issues. The latter group also included mass killings or serial homicides.
The findings showed that conventional stranger homicides often involved accomplices, were more likely to be committed against male victims, and typically took place at night. In contrast, nonconventional stranger homicides were more frequently carried out by individuals acting alone, were more likely to happen in public spaces during the day, and were often linked to offenders suffering from severe mental disorders.
The data revealed some distinct differences between the crime scenes and the offenders in each category. Conventional homicides were often triggered by spontaneous conflicts or occurred in the context of criminal activities like robbery or gang violence. These incidents were more likely to involve accomplices, and the offenders were more frequently intoxicated at the time of the crime.
Nonconventional stranger homicides were more varied in their characteristics but had certain commonalities. Offenders in this group were less likely to be intoxicated and more likely to initiate contact with the victim, often targeting them randomly in public places. These offenders were also more likely to be adjudged to have severe mental health issues upon psychiatric evaluation. The study indicated that these nonconventional homicides were largely “acts of madness”, unpredictable and unprovoked, aligning with the archetypal notion of stranger violence.
A significant portion of nonconventional homicides was found to be linked to mental health issues. These crimes were usually committed by individuals with severe mental disorders, such as chronic psychosis or other debilitating conditions. The unpredictability and irrationality of these acts contributed to the fear that society often associates with stranger homicides, reinforcing the notion of “random acts of violence”.
