The Swedish School Attack in Trollhättan.

This is a case report of the offender and offense characteristics of a targeted attack on a Swedish school using a sword, with a particular focus upon the offender's history, the relationship between mental disorder and ideology, and whether or not it was an act of terrorism. Findings indicate that the offender had no drug or psychiatric treatment history, but postoffense analysis suggests autism spectrum disorder, depression, and both suicidal ideation and intent. The offender planned and prepared for his attack, and the triggering event appeared to be the loss of a temporary job. He expressed chronic anger concerning immigrants to Sweden and blamed them for his failures. Comparison of the fact pattern to other cases of lone actor terrorism with the Terrorist Radicalization Assessment Protocol (TRAP-18) empirically demonstrates excellent criterion validity with other lone actor terrorists in Europe and North America-including right wing extremists-and contributes to further understanding of ideologically motivated mass murder.