On 22 October 2015, 21-year-old Anton Lundin Pettersson attacked Kronan School in Trollhättan, Sweden, with a sword. He killed a teacher and a male student, stabbed another male student and a teacher, and died later of the gunshot wounds he received during his apprehension

According to reports, Ahmed Hassan, 15, was stabbed and died later of his wounds. Ahmed was sitting in a class when the killer knocked on the door. Hassan opened it and was stabbed in the abdomen,

Hassan was born in Somalia. He moved to Sweden three years ago.