Bolshevik Party's underground period. Early in 1917, Bokii was arrested and sentenced to exile in Yakutsk, but before he was transported, the Tsar Nicholas II was overthrown by the February Revolution, and he was released and resumed his leading role on the Petrograd City Committee, of which he served as Secretary from April 1917 to March 1918. He was also a member of the Petrograd Military Revolutionary Committee during October and November 1917 — the institution which planned and carried out the Bolshevik uprising on November 7. Bokii was recognized as a supporter of the "Left Communists" headed by Nikolai Bukharin who sought to fight a revolutionary war against German invaders rather than signing a separate peace in the period immediately after the Bolshevik uprising. Together with Stanislav Kosior, Bokii was one of five signatories of a declaration of the Executive Commission of the Petersburg Committee directed at the governing Central Committee of the Russian Communist Party, which warned: "The political line now being pursued by the Central Committee ... is directed toward conclusion of a so-called 'obscene' peace [which] would result in the abdication of our principles ... and the certain death of our party as a revolutionary vanguard. ... We have ample grounds for asserting that signing an 'obscene' peace would run counter to the opinion of the majority in our party. ... If our present peace policy continues ... a split threatens our party." A special party conference to decide the peace question was called for by Bokii and his comrades of the Peterburg Committee. German forces continued their advance on Petrograd in the interim and February and March 1918 saw Bokii take on an additional role organizing the city's defenses as member of the Committee for the Revolutionary Defense of Petrograd. Ultimately, the German offensive was halted when Lenin and the party Central Committee won the day by signing the Treaty of Brest-Litovsk with the government of Imperial Germany on March 3, 1918. Territory including a quarter of Russia's population and a quarter of its industry were ceded to the Germans under the onerous terms of the peace. Secret police activities On March 13, 1918, Bokii went to work as deputy head of the Extraordinary Commission (Cheka) of the Northern oblast and Petrograd. He remained in this position until the end of August 1918, at which time he was briefly made the head of that same