 Beloborodov was arrested in 1936, early in Stalin's great purge of the upper echelons of the Communist Party, but resisted making the confession required of him, so although his name was mentioned at the trial of Karl Radek and others in January 1937, he was not produced in court.In May 1937, Stalin sent a note to Nikolai Yezhov, head of the NKVD, saying