Abwehr : Nazi Germany
Abwehr was the German military intelligence organization. After Adolf Hitler came to power Abwehr often came into conflict with the Nazi controlled organizations, the SD Security Service and the Gestapo.
In January 1935 Wilhelm Canaris became the new head of Abwehr. Soon afterwards he negotiated an agreement with Reinhard Heydrich about the role of the two organizations. However, both continued to train their own spies for duty in Germany and in foreign countries. Hugo Bleicher was particularly successful at tracking down agents in France.
In 1943 several members of Abwehr became active in the resistance movement in Germany. This included Wilhelm Canaris, Hans Oster, Helmuth von Moltke, Hans Gisevius, Josef Muller, Hans Dohnanyi and Peter von Wartenburg.
The Gestapo began to investigate members of Abwehr and Hans Dohnanyi was arrested and Hans Oster was suspended from duty.
In June, 1944 Heinrich Himmler took over Abwehr and after the July Plot the organization was absorbed into the SD Security Service. Over the next few months Wilhelm Canaris, Hans Oster, Helmuth von Moltke, Hans Dohnanyi and Peter von Wartenburg were all found guilty of treason and executed.
Primary Sources
(1) Walter Warlimont was interviewed by Basil Liddell Hart about Abwehr in his book The Other Side of the Hill (1948)
The organization of Intelligence was a source of rivalry and ambitions, and consequently of heavy mistakes on our side. Originally and up to 1944 the 'Office Foreign Affairs and Counter-Intelligence', incorporated in the O.K.W. and conducted by Admiral Canaris, assembled the intelligence and furnished it to the three forces for evaluation. Thus the Armed Forces Operations Staff, in its capacity as the operations branch for the Western theatre, was dependent mainly on the O.K.H. section 'Foreign Armies West', and in addition on the corresponding sections of the Navy and Air Force. Early in 1044 the office of Canaris was dissolved by order of Hitler, chiefly for political reasons, and he himself dismissed. The Intelligence now became a part of the Reichs Security Central Office, headed by the S.D. - Chief, Kaltenbrunner. He, for personal reasons, often deviated from the prescribed official way and sent or delivered important news, or what he deemed such, directly to Hitler or Jodl. In the end, as a natural consequence of such a system, there was much trouble and little intelligence. When finally, on the afternoon of the 5th June, 1944, Kaltenbrunner believed he had sure indications of the impending invasion, and reported them to Jodl, Jodl paid no attention to it - or, at least, informed neither his staff nor Hitler.
As regards the site of the landing. Hitler was the first who came to the conclusion that Normandy was the most probable spot. On May 2nd and he ordered that anti-aircraft and anti-tank weapons were to be reinforced throughout that sector on that calculation. Hitler's view was based on intelligence received as to troop movements in Britain. Two main troop concentrations had been observed there - one in the south-east, consisting of British troops, and the other in the south-west consisting of American troops. The situation of the Americans, in particular, led Hitler to anticipate an attack launched against the western part of Normandy. Besides his deductions from troop movement!, Hitler based his conclusions on the consideration that the Allies, from the outset, would need a big port which had to be situated in such a way as to be quickly protected by a rather short front line. These conditions would be essentially met by the port of Cherbourg and the Cotentin Peninsula. We were not quite convinced that Hitler was right, but he kept harping on it, and demanded more and more reinforcements for the Normandy sector. We generals figured along the lines of our regular military education whereas Hitler figured, as he always did, out of intuition.