Of Roosevelt's advisors, only Hopkins and Admiral William D. Leahy knew of this secret wartime agreement, and Leahy, possibly because he never believed that the atomic bomb would work, and was therefore perhaps not paying much attention, had only a muddled recollection of what had been said.[119][120] When Wilson raised the Hyde Park Aide-Mémoire in a Combined Policy Committee meeting in June 1945, the American copy could not be found.[121] The British sent Stimson a photocopy on 18 July.[122] Even then, Groves questioned the document's authenticity until the American copy was located many years later in the papers of Vice Admiral Wilson Brown, Jr., Roosevelt's naval aide, apparently misfiled in Roosevelt's Hyde Park papers by someone unaware of what Tube Alloys was, and who thought it had something to do with naval guns or boiler tubes.[121][123][124]