▁started ▁his ▁career ▁at ▁the ▁Air ▁Staff . ▁He ▁married ▁Marian ne ▁B äck l und ▁( born ▁ 1 9 3 5 ) ▁and ▁they ▁had ▁two ▁children . ▁They ▁lived ▁in ▁a ▁small ▁house ▁on ▁L iding ö . ▁At ▁the ▁time ▁of ▁his ▁arrest ▁Str ö berg ▁was ▁a ▁lieutenant ▁colon el ▁and ▁head ▁of ▁Air ▁Staff ' s ▁Sign al ▁Communic ations ▁Department , ▁and ▁had ▁access ▁to ▁information ▁on ▁all ▁of ▁the ▁military ▁communication ▁systems . ▁ ▁Ar rest ▁Str ö berg ▁was ▁arrested ▁on ▁ 2 0 ▁May ▁ 1 9 8 3 ▁at ▁the ▁Central ▁Post ▁Office ▁on ▁Vas ag atan ▁in ▁Stockholm ▁by ▁the ▁Swedish ▁Security ▁Service ▁after ▁he ▁tried ▁to ▁collect ▁a ▁poste ▁rest ante ▁letter ▁addressed ▁to ▁" S ven - R ol and ▁Lar sson ". ▁A ▁few ▁weeks ▁earlier ▁the ▁Polish ▁Emb ass y ▁in ▁Stockholm ▁received ▁a ▁letter ▁signed ▁" S ven - R ol and ▁Lar sson " ▁with ▁a ▁series ▁of ▁class ified ▁military ▁information ▁and ▁a ▁request ▁for ▁SE K ▁ 2 5 , 0 0 0 ▁($ 3 , 4 0 0 ) ▁in ▁exchange ▁for ▁further ▁information . ▁The ▁money ▁would ▁then ▁be ▁sent ▁to ▁" S ven - R ol and ▁Lar sson ". ▁Sus pected ▁they ▁were ▁being ▁set ▁up , ▁the ▁Polish ▁Emb ass y ▁contact ed ▁the ▁Ministry ▁for ▁Foreign ▁Affairs ▁who ▁handed ▁the ▁letter ▁over ▁to ▁the ▁Swedish ▁Security ▁Service ▁who ▁set ▁up ▁a ▁trap ▁for ▁Str ö berg .