acting as he did remain a mystery. He read in the newspapers that Hitler would be addressing a Nazi Party meeting on 8 November, in the Bürgerbräukeller, a beer hall in Munich where Hitler had launched the Beer Hall Putsch on the same date in 1923. Stealing explosives from his workplace, he built a powerful time bomb, and for over a month managed to stay inside the Bürgerbräukeller after hours each night, during which time he hollowed out the pillar behind the speaker's rostrum to place the bomb inside. On the night of 7 November 1939, Elser set the timer and left for the Swiss border. Unexpectedly, because of the pressure of wartime business, Hitler made a much shorter speech than usual and left the hall 13 minutes before the bomb went off, killing seven people. Sixty-three people were injured, sixteen more were seriously injured with one dying later. Had Hitler still been speaking, the bomb almost certainly would have killed him. This event set off a hunt for potential conspirators which intimidated the opposition and made further action more difficult. Elser was arrested at the border, sent to the Sachsenhausen Concentration Camp, and then in 1945 moved to the Dachau concentration camp; he was executed two weeks before the liberation of Dachau KZ. Aeroplane assassination attempt In late 1942, von Tresckow and Olbricht formulated a plan to assassinate Hitler and stage a coup. On 13 March 1943, returning from his easternmost headquarters FHQ Werwolf near Vinnitsa to Wolfsschanze in East Prussia, Hitler was scheduled to make a stop-over at the headquarters of Army Group Centre at Smolensk. For such an occasion, von Tresckow had prepared three options: Major Georg von Boeselager, in command of a cavalry honor guard, could intercept Hitler in a forest and overwhelm the SS bodyguard and the Führer in a fair fight; this course was rejected because of the prospect of a large number of German soldiers fighting each other, and a possible failure regarding the unexpected strength of the escort. A joint assassination could be carried out during dinner; this idea was abandoned as supporting officers abhorred the idea of shooting the unarmed Führer. A bomb could be smuggled on Hitler's plane. Von Tresckow asked Lieutenant Colonel Heinz Brandt, on Hitler's staff and usually on the same plane that carried Hitler, to take a parcel with him, supposedly the prize of a bet won