Matters came to a head in 1937 when Hitler decided to help Joseph Stalin in the latter 's purge of the Soviet military . Hitler ordered that the German Army staff should be kept in the dark about Stalin 's intentions , for fear that they would warn their Soviet counterparts due to their long-standing relations . Accordingly , special SS teams , accompanied by burglary experts from the criminal police , broke into the secret files of the General Staff and the '' Abwehr '' and removed documents related to German-Soviet collaboration . To conceal the thefts , fires were started at the break-ins , which included '' Abwehr '' headquarters
purge
Great Purge
Abwehr