Party, 1898. Menshevik after the split in the party. Changed over to the Bolsheviks in summer 1917, member of the Central Committee of the Bolshevik Party, July 1917. Active participant in the Bolshevik take-over, October 1917, in Petrograd.
Appointed head of the Petrograd Cheka, March 1918. Assassinated (shot) by the SR student Leonid Kannegiesser, whose friend had been executed by the Cheka shortly before.