Pospelov subsequently spoke to Dr. Kirchakov and former nurse Trunina, former members of the party, who had been mentioned in a letter by another member of the commission, Olga Shatunovskaya, as having knowledge of the Kirov murder. Kirchakov confirmed that he did talk to Shatunovskaya and Trunina about some of the unexplained aspects of the Kirov murder case, and agreed to provide the Commission with a written deposition. He stressed that his statement was based on the testimony of one Comrade Yan Olsky, a former NKVD officer who was demoted after Kirov's murder and transferred to the People's Supply System. In his deposition, Kirchakov wrote that he had discussed the murder of Kirov and the role of Fyodor Medved with Olsky. Olsky was of the firm opinion that Medved, Kirov's friend and NKVD security chief of the Leningrad branch, was innocent of the murder. Olsky also told Kirchakov that Medved had been barred from the NKVD Kirov assassination investigation. Instead, the investigation was carried out by a senior NKVD chief, Yakov Agranov, and later by another NKVD bureau officer, whose name he did not remember. During one of the committee sessions, Olsky said he was present when Stalin asked Leonid Nikolayev why Comrade Kirov had been killed. To this Nikolayev replied that he carried out the instruction of the "Chekists" (meaning the NKVD) and pointed towards the group of "Chekists" (NKVD officers) standing in the room; Medved was not among them.