 Meanwhile, in Moscow, the Underground Anarchists were formed by Kazimir Kovalevich and Piotr Sobalev to be the shock troops of the Revolution, infiltrating Bolshevik ranks and striking when least expected.On 25 September 1919, the Underground Anarchists struck the Bolsheviks with the heaviest blow of the Revolution.The headquarters of the Moscow Committee of the Communist Party was blown up, killing 12 and injuring 55 Party members, including Nikolai Bukharin and Emilian Iaroslavskii.