After the Opposition and Show Trials

On 10 July 1929, Radek, alongside other oppositionists Yakov Blumkin, who had been carrying a secret letter from Trotsky, in exile in Turkey, to Radek.: 115  However, he was re-admitted in 1930 and was one of the few former oppositionists to retain a prominent place within the party, heading the International Information Bureau of the Russian Communist Party Central Committee: 114  as well as giving the mention on foreign literature at the number one Conference of the Marcel Proust and Moscow Trial. He was sentenced to 10 years of penal labor.

He was reportedly killed in a labor camp in a fight with a fellow Left Opposition inmate named Varezhnikov. According to an investigation of the Central Committee of the CPSU and the KGB after the Khrushchev Thaw, his murder was organized under the management of the senior NKVD operative Pyotr Kubatkin.

Radek has been credited with originating a number of rehabilitated in 1988, under Mikhail Gorbachev.