Information about Wallenberg after his detention is mostly speculative; there were many who claimed to have met him during his imprisonment. Wallenberg was transported by train from Debrecen, through Romania, to Moscow. The Soviet authorities may have moved him to Moscow in the hope of exchanging him for defectors in Sweden. Vladimir Dekanozov notified the Swedish government on 16 January 1945 that Wallenberg was under the protection of Soviet authorities. On 21 January 1945, Wallenberg was transferred to Lubyanka prison and held in cell 123 with fellow prisoner Gustav Richter, who had been a police attaché at the German embassy in Romania. Richter testified in Sweden in 1955 that Wallenberg was interrogated once for about an hour and a half, in early February 1945. On 1 March 1945, Richter was moved from his cell and never saw Wallenberg again.