The staff of the Cheka was also changed. Even the more radical Social Revolutionaries were not allowed into Popov's headquarters. All Bolshevik elements were removed from the detachment. Most of the Finnish Red Army soldiers, who previously formed the basis of the detachment, went to the Czechoslovak front; Popov drove out many of those remaining. The detachment was joined by a group of Black Sea sailors, as well as formerly disarmed anarchists. 2–3 days before the uprising, Popov kept his detachment in full combat readiness, unnerving everyone with the "data" of their intelligence that the German counter-revolutionaries were going to disarm the detachment and arrest Popov himself. On the night of Friday to Saturday, Popov sounded the alarm that an attack was being prepared that night. On the eve of the rising, Popov personally led anti-Soviet agitation in the detachment and went on to play an active role in the rebellion.