In September 1917, the house arrest was lifted. At the end of the following month the Prime Minister, Alexander Kerensky, was deposed in the October Revolution and the Bolsheviks seized power. With a permit to travel issued by Peter Polotsov, a former army colleague of Michael's who held a command in Saint Petersburg, the family planned to move to the greater safety of Finland. Valuables were packed and the children were moved to an estate south of Gatchina owned by Vladimir Dmitrievich Nabokov, the brother of one of Natalia's closest friends (Nadine Vonlyarlarskaya) and the father of the famous writer, Vladimir Vladimirovich Nabokov. The Bolsheviks discovered their plan, however, and their escape was blocked. The children returned to Gatchina, and they were once again under house arrest. Natalia managed to gain access to her safety deposit box, by claiming that she needed to examine some papers at the bank, and thus retrieved as much of her jewellery as she could conceal without arousing suspicion. The house arrest was lifted in November, but on 7 March 1918 Michael and Nicholas Johnson—who had been his secretary since December 1912—were re-arrested on the orders of Moisei Uritsky, the Head of the Petrograd secret police. They were imprisoned at Bolshevik headquarters in the Smolny Institute.