Police investigating Sweden's worst mass shooting were still trying to establish a motive as to why a lone gunman opened fire at an education campus in the southern city of Orebro, killing 10 people.

The suspected gunman in a deadly school shooting in Sweden shot himself after killing 10 people on Tuesday, police believe. Armed police exchanged fire with an unnamed shooter at Risbergska School in Örebro, 125 miles west of Stockholm, in what Swedish prime minister Ulf Kristersson has described as the worst mass shooting in the country’s history.

Police said “around 10 people” were killed in a shooting at a school in central Sweden on Tuesday, with the suspected perpetrator believed to be among those dead.