After the surrender of Narvik on 9 April 1940, Sundlo was accused of treason by his divisional commander, General Carl Gustav Fleischer. However, the post-war trials only found that Sundlo had committed "negligent offences" at Narvik in 1940. He was still found guilty for a number of other acts during the occupation, and sentenced to life in prison. A minority of three of the eight judges at his trial voted for a death sentence. Konrad Sundlo was pardoned in 1952 and died in 1965.