The British forces occupied Flensburg on 5 May 1945; initially, nothing changed in the daily routine at the Mürwik Naval Academy. Returning drunk in the night of 13/14 May 1945, Lüth failed to respond to the sentry's challenge and was shot in the head by 18-year-old seaman Mathias Gottlob, a German guard. The officer in charge immediately reported the incident, contacting Grand Admiral Karl Dönitz. Dönitz's adjutant, who had accepted the call, initially thought that it was a bad joke. He then called Lüth's brother, Joachim, as the two siblings had been staying together. It was he who informed Lüth's wife and their four children that Lüth had died.