[3][4] He was a teacher at Ferny Grove State High School and taught the subjects of manual arts, media and business.
[7] A report stated he often retreated into fantasy worlds, had trouble thinking rationally, lacked social skills, and needed psychotherapy to assist his issues with anxiety and depression.
[7] Amundsen gained notoriety in May 2006, after a stockpile of explosives and detonators were found in his home which caused the school he worked at to be evacuated and searched.
[3][4][5][8][9] On 10 May 2006, the school was closed for most of the morning as police with sniffer dogs checked classrooms, before they declared it safe for students and staff to resume lessons.
[12][2] In February 2008, he was jailed for six years for offences surrounding a plot to scare the parents of his ex-girlfriend so that he would win back their daughter.