Rubuta ci gaba don wannan sakin layi - A watan Yulin 1940, Roller, bayan da ya tsere daga sake kamawa da hukumomin Romania suka yi, ya bar Bessarabia, wanda 'yan Soviet suka mamaye kwanan nan
Ka yi haƙuri. Ya kasance na ɗan lokaci a Reni, a cikin Ukrainian SSR. Roller daga baya ya koma Moldavian SSR, a Chișinău, inda ya fara aiki don Masana'antar Taba sigari ta birni. A watan Yunin 1941, 'yan kwanaki kafin a fara Operation Barbarossa, ya aika da takardar shaidarsa ga Boris Stefanov, yana neman a yi la'akari da shi don zama memba na Jam'iyyar Kwaminis ta Tarayyar Soviet. An shiga cikin rukunin PCdR a Moscow, Roller ya ci gaba da aiki a ƙarƙashin Pauker, wanda shi ma ya shiga cikin al'ummar 'yan gudun hijirar Romania. Ya kuma halarci kwalejin Tarihi na Jami'ar Jihar Moscow. An san kadan game da ayyukan Roller a farkon 1944, lokacin da canjin yanayi a Gabas ta Gabas ya nuna nasarar Soviet a kan Axis Powers. An ce, ya daina biyan kuɗin membobin sa na PCdR, wanda zai iya nuna cewa ya shagaltu da aikin jam'iyya, kuma ya shirya don aiki a cikin Romaniya mai gurguzu. Bayan ya kwashe wani lokaci a Cibiyar No. 205 (tsohon makarantar Comintern), a watan Disamba na 1944 shi kadai ne ɗan asalin Romania da ke koyar da fursunonin yaƙi a Makarantar Antifascist ta Krasnogorsk. Yayin da yake nan, ya ba da shawarar yin amfani da Alexandru Bârlădeanu da Haia Grinberg don taimaka masa da ƙwararrun azuzuwan.