Attached is a 1948 report concerning the war-time collaboration between the O.S.S. and the Soviet N.K.V.D.
"This is the story of how Russia got military secrets from the United States during W.W. II. It is a story that has little to do with the spy ring that congressional committees are trying to prove existed during the war period (The Gouzenko Affair: read about it here). But it does throw light on the methods and purposes of the so-called 'spy ring'".
"Military information was going to Russia as a matter of routine, by official channels, on an organized basis, all during the period when United States Communists and their friends were supposed to be spying out bits of information to send... As an ally of the U.S. in the war against Germany, Russia had free access to far more information than the so-called 'spy ring' claims..."