Arrested in Warsaw in January 1927, he was released on 30 April, based on personal assurances issued on his behalf by Stanisław Szwalbe and Zygmunt Zaremba. During the Fourth Congress of the Communist Party of Poland (KPP, the new name of the KPRP), which took place from 22 May to 9 August 1927, Bierut became a member of the Temporary Secretariat of the Central Committee again. In November, the party sent him to the International Lenin School in Moscow. He received positive evaluations there, except for not being entirely free of ideological right-wing errors, characteristic, in the school's opinion, of the Polish communist party.