 He remained in the Polish embassy in Moscow as one of the officials entrusted with searching for roughly 22,000 missing Polish officers.He left Russia in July 1942 and reached Great Britain, where he remained active in the Polish government in exile.He was also co-author of "The crime of Katyn; facts & documents", one of the first monographs on the mass murder of Polish officers by the Soviets, published in 1948.