Member of the SR Party, 1914. Left the SRs, 1917. In Moscow on 6 July 1918 assassinated the German Ambassador, Count Mirbach, (as a protest against the terms of the BrestLitovsk peace treaties, which the Left SRs, partners in the coalition government with the Bolsheviks, completely rejected). This served as the signal for the left wing SR uprising in Moscow, which was defeated only with difficulty by Latvian Cheka detachments.
Took part in the uprising, and went underground. Maximalist SR in 1919 in the Ukraine, trying to fight the German occupation army. Soon amnestied (May 1919).
Worked closely with Trotsky in the Army and Navy Ministry (People’s Commissariat) and in the secret police (Cheka, GPU, under Dzerzhinskii, Menzhinskii and Trilisser). Later met Trotsky in exile in Constantinople and took a letter from him to his followers in the USSR (both facts acknowledged later by Trotsky). Arrested and executed.