▁remained ▁susp icious ▁of ▁Phil by , ▁but ▁l unch ed ▁with ▁him ▁every ▁week ▁in ▁Washington . ▁ ▁However , ▁a ▁more ▁serious ▁threat ▁to ▁Phil by ' s ▁position ▁had ▁come ▁to ▁light . ▁During ▁the ▁summer ▁of ▁ 1 9 4 5 , ▁a ▁Soviet ▁ci pher ▁cl erk ▁had ▁re used ▁a ▁one ▁time ▁pad ▁to ▁transmit ▁intelligence ▁traffic . ▁This ▁mistake ▁made ▁it ▁possible ▁to ▁break ▁the ▁normally ▁im pre gn able ▁code . ▁Cont ained ▁in ▁the ▁traffic ▁( inter cept ed ▁and ▁dec rypted ▁as ▁part ▁of ▁the ▁Ven ona ▁project ) ▁was ▁information ▁that ▁documents ▁had ▁been ▁sent ▁to ▁Moscow ▁from ▁the ▁British ▁Emb ass y ▁in ▁Washington . ▁The ▁intercept ed ▁messages ▁revealed ▁that ▁the ▁British ▁Emb ass y ▁source ▁( ident ified ▁as ▁" H omer ") ▁travel led ▁to ▁New ▁York ▁City ▁to ▁meet ▁his ▁Soviet ▁contact ▁twice ▁a ▁week . ▁Phil by ▁had ▁been ▁brief ed ▁on ▁the ▁situation ▁shortly ▁before ▁reaching ▁Washington ▁in ▁ 1 9 4 9 ; ▁it ▁was ▁clear ▁to ▁Phil by ▁that ▁the ▁agent ▁was ▁Donald ▁Mac lean , ▁who ▁worked ▁in ▁the ▁British ▁Emb ass y ▁at ▁the ▁time ▁and ▁whose ▁wife , ▁Mel inda , ▁lived ▁in ▁New ▁York . ▁Phil by ▁had ▁to ▁help ▁discover ▁the ▁identity ▁of ▁" H omer ", ▁but ▁also ▁wished ▁to ▁protect ▁Mac lean . ▁ ▁In ▁January ▁ 1 9 5 0 , ▁on ▁evidence ▁provided ▁by ▁the ▁Ven ona ▁intercept s , ▁Soviet ▁atomic ▁sp y