The Government Delegate, together with most members of the Council of National Unity and the Commander-in-chief of the Armia Krajowa, were invited by Soviet general Ivan Serov (with agreement of Joseph Stalin) to a conference on their eventual entry to the Soviet-backed Provisional Government. Some historical accounts say approaches were made in February, with others saying March 1945. The Polish politicians were presented with a warrant of safety, but were instead arrested in Pruszków and brutally beaten by the NKVD on 27 and 28 March. Leopold Okulicki, Jan Stanisław Jankowski and Kazimierz Pużak were arrested on the 27th with 12 others the following day. Alexander Zwierzynski had been arrested earlier. They were brought to Moscow for interrogation in the Lubyanka.