Immigrant Background and Registration as a Suspect of Firearm Homicide in Sweden – A 21-Year Follow-Up Study

Using nationwide register data, individuals aged 15–60 years registered as suspects of firearm homicide, attempted firearm homicide, or conspiracy/preparation to commit such offenses (firearm homicide+) between 2000 and 2020 were matched to population controls. Conditional logistic regression examined the association between immigrant background and registered suspicion of firearm homicide+, adjusting for socioeconomic factors, psychiatric and substance use disorders, and prior criminality. Among 1,745 registered suspects, 71.1% had an immigrant background. Individuals born in Sweden to two foreign-born parents had the highest odds of being registered as a suspect of firearm homicide+ (crude OR = 14.7), remaining high after adjustment. Drug use disorder, defined using register-based health-care, prescription, and criminal justice data, was registered in over 66% of suspects and was strongly associated with the outcome. Our findings show that registered suspicion of firearm homicide+ was strongly associated with immigrant background and drug use disorder, but the study does not establish causal mechanisms underlying these associations.