Kammala wannan jumla: Felfe ya shiga aikin leken asiri "Der Sicherheitsdienst" a shekarar 1943. A watan Agusta 1943 an tura shi zuwa Switzerland inda, a matsayin shugaban mahimmin sashen Switzerland na hukumar, nauyinsa ya hada da yada takardun kudi na Burtaniya a matsayin wani ɓangare na dabarun da za a yi amfani da ita don raunana kuɗin Birtaniya a duniya. Zuwa karshen yakin an daukaka shi zuwa matsayin SS-Obersturmführer (kusan daidai da Laftanar na farko) kuma, a watan Disamba na 1944, an tura shi zuwa Netherlands tare da umarnin shirya ƙungiyoyin masu tayar da hankali a bayan abin da yanzu ya zama layin gaba na haɗin gwiwa. A cewar wani rahoto na 'yan jarida a shekarar 1969 yawancin kuzarinsa yayin da yake cikin Netherlands ya nuna kishiyar kansa da mahaifinsa, wani jami'in bincike na aikata laifuka da ke Dresden wanda yake da halin nuna iko, wanda asalinsa memba ne na' yan tsiraru na Sorbian na Jamus. Kamar yadda
Injin yaƙin Jamus ya koma baya a duk faɗin Turai, Felfe ya nemi Gestapo ta tsananta wa membobin 'yan tsirarun Sorbian a cikin ƙasarsa ta Saxon.