At the end of 1943 the SS and the Gestapo arrested several prominent Germans involved in plotting to overthrow Adolf Hitler, including Dietrich Bonhoffer, Klaus Bonhoffer, Josef Muller and Hans Dohnanyi. Others under suspicion, such as Wilhelm Canaris and Hans Oster, were dismissed from office in January 1944. Major Claus von Stauffenberg emerged as a leader of the group of German Army officers opposed to Nazi rule, and began to plan for the assassination of Adolf Hitler, Hermann Goering and Heinrich Himmler, and for a takeover by the Army. Once these three prominent Nazis had been killed, the plan called for troops in Berlin and other major German-controlled areas, commanded by his co-conspirators, to seize key government buildings, telephone and signal centres and radio stations. At least six attempts were aborted before von Stauffenberg decided on trying again during a conference attended by Hitler on 20 July 1944. It was decided to abandon the plans to kill Goering and Himmler at the same time, and to focus solely on removing the Führer. Von Stauffenberg carried the bomb in a briefcase and placed it on the floor beside Hitler before excusing himself to make a phone call. The bomb exploded killing four men in the hut. Hitler was injured but survived the bomb blast. The plan that called for Ludwig Beck, Erwin von Witzleben and Erich Fromm to take control of the German Army and declare martial law was abandoned when it became known that Hitler had survived the assassination attempt. In an attempt to protect himself, Fromm organized the execution of Claus von Stauffenberg and two other conspirators, Friedrich Olbricht and Werner von Haeften, in the courtyard of the War Ministry. It was later reported that von Stauffenberg died shouting "Long live free Germany". As a result of the 20 July Plot, the new chief of staff, Heinz Guderian, demanded the resignation of any officer who did not fully support the ideals of the Nazi Party and presided over the Army Court of Hono