According to his stepdaughter's interview, while living in poverty, at his place in central Vilnius he also hid from the Nazis a Jewish girl (who later disappeared), and supplied ghetto Jews with false documents allowing emigration.
He spent 1945-1950 teaching at the University of Vilnius again, but then was arrested by the Soviet authorities, accused of "anti-Soviet activities" and "relations with Zionist organizations" and sentenced to 15 years of labor camps.