About 90 minutes after the Oslo explosion, a gunman in police uniform, believed to be Anders Behring Breivik, got on a ferry about 40 kilometres (25 miles) northwest of Oslo. The ferry went to the island of Utøya in lake Tyrifjorden. The island was the site of the Labour Party's annual Workers' Youth League (AUF) youth summer camp. Once on the island, the gunman began to shoot the mainly adolescent campers, before finally being captured.