Operation Valkyrie
By the time Stauffenberg's plane reached Berlin at about 15:00, General Erich Fellgiebel, an officer at Rastenburg who was in on the plot, had rung the Bendlerblock and told the plotters that Hitler had survived the explosion. This was a fatal step (literally so for Fellgiebel and many others), because the Berlin plotters immediately lost their nerve, and judged, probably correctly, that the plan to mobilise Operation Valkyrie would have no chance of succeeding once the officers of the Reserve Army knew that Hitler was alive. There was more confusion when Stauffenberg's plane landed and he phoned from the airport to say that Hitler was dead. The Bendlerblock plotters did not know whom to believe. Finally at 16:00 Olbricht issued the orders for Operation Valkyrie to be mobilised. The vacillating General Fromm, however, phoned Keitel, who assured him that Hitler was alive, and demanded to know Stauffenberg's whereabouts. This told Fromm that the plot had been traced to his headquarters, and that he was in mortal danger.