In 1958, at a performance of "The Diary of Anne Frank" in Vienna, Simon Wiesenthal was challenged by a group of protesters who asserted that Anne Frank had never existed, and who challenged Wiesenthal to prove her existence by finding the man who had arrested her. Wiesenthal indeed began searching for Karl Silberbauer and found him in 1963. When interviewed, Silberbauer admitted his role, and identified Anne Frank from a photograph as one of the people arrested. Silberbauer provided a full account of events, even recalling emptying a briefcase full of papers onto the floor. His statement corroborated the version of events that had previously been presented by witnesses such as Otto Frank.