Investigations dragged on inconclusively until April 1945, when orders were received to dispose of the various remaining prisoners of the 20 July plot. Canaris' personal diary was discovered and presented to Hitler in early April 1945, implicating him in the conspiracy. Canaris was placed on trial by an SS summary court presided over by Otto Thorbeck with Walter Huppenkothen as prosecutor. He was charged with and found guilty of treason. He was sentenced to death. Together with his deputy general, Hans Oster, military jurist General Karl Sack, theologian Dietrich Bonhoeffer and Ludwig Gehre, Canaris was humiliated before witnesses. Canaris was led to the gallows naked and executed on 9 April 1945 at the Flossenbürg concentration camp, just weeks before the end of the war. A prisoner claimed he heard Canaris tap out a coded message on the wall of his cell on the night before his execution, in which he denied he was a traitor and said he acted out of duty to his country.