Military Intelligence is a discipline, and like all proud disciplines it does require dedication and training, and it's reputation is judged by it's relationship with informed perspectives that are supported by available evidence. Intelligence officers are like the scientists of weather forecasting, and woe unto he who relies on the Farmers Almanac. Abwehr is the German word for Defense. The Abwehr was the name for a military intelligence service formed in 1920 contrary to the provisions of the Versailles Treaty within the agreed to Reich Ministry that was to be solely devoted to military matters, a limited army, a very limited navy, and hardly any air force. In the 1930's political interests within the new Germany had a few secrets of their own, and in 1937 these political interests raided the offices of the Abwehr to destroy files that reflected a truth that might have damaged their own carefully crafted reputations. They assumed that the Abwehr was also political player in the developing political circumstances within Germany. It was a quality of intense distrust within the upper levels of the new German hierarchy many of whom were close to feral and equally as short-sighted as many appear to be here in the USA in the year 2019. And no accident that a dictator is or was their head of state.
What happened was this, Stalin and Hitler had a dictator head of state kind of relationship, it's a sort of homo-erotic bro-mance only between power lusting boy Porcupines, and Hitler kindly offered Stalin information, that would be provided by his Abwehr, about suspect individuals within the Red Army's officer corps. Stalin accepted, and Hitler uncertain of the loyalties within the German officer corps thought it best to keep his arrangement, or deal, with Stalin secret. The suspicion was that because of relationships that had developed between the German and Soviet officer corps toward the end of the First World War, German officers might warn their counterparts, who might then escape the labor camps. Stalin conducted a very successful purge of his officer corps, the result was a win for Hitler, the effectiveness and capacities of the Red Army was very badly damaged and it was a win for Stalin who was more interested in his own survival through absolute personal loyalty than he was in his country's military effectiveness. Meanwhile in Germany political interests were very nervous of the Abwehr's information gathering, and had no inclination to believe that the information within the Abwehr's possession wouldn't be used for personal political gain by the Chief of the Abwehr, who at the time believed that his country had done so badly in the First World War as a result of a failure in the mission of military intelligence. I think it was Nietzsche who added his voice to the view that with us people the same events twist on an axis, turn endlessly, nothing really changes.