for acts of terrorism. Gershuni thought so highly of Azef that he nominated him as his successor, and so when Gershuni was arrested in spring 1903 after being betrayed by another double agent, Azef became head of the combat organisation, with Boris Savinkov as his deputy. Azef thus became both Russia's leading terrorist and most highly paid police informant. In that position he organized the assassination of Vyacheslav Plehve in 1904. Plehve, as minister of the interior, was Azef's nominal employer and the person who had ultimately authorised him to infiltrate the Socialist Revolutionary Party. Plehve had also made Gershuni's arrest the police's main priority, thus facilitating the rise of Azef. In 1905, Azef would organise the assassination of the Tsar's uncle Grand Duke Sergei Alexandrovich of Russia, who served as Governor-General of Moscow. The success of those two assassinations gave Azef immense prestige within the Socialist Revolutionary Party. Because he was so trusted, he was able to deliver a long list of his rivals within the SR Party over to the Okhrana to be arrested. Their names included Anna Yakimova, a veteran of the plot to kill Tsar Alexander II who had served 24 years in prison, and Zinaida Kopolyannikova, who was hanged in August 1906 for assassinating the head of the Tsar's lifeguards. In 1905 alone, according to researchers who accessed police records after the 1917 revolution, Azef informed against 17 of his subordinates within the SR Combat Organisation. The assassinations of the Interior Minister and the Tsar's uncle also set off a crisis within the Okhrana. The Director of Police, Alexei Lopukhin, resigned, and was replaced by his rival Pyotr Rachkovsky, whom he despised. One of Rachkovsky's first actions was to sack Leonid Ratayev, who had been acting as Azef's handler, and to personally take over supervision of him. Azef's double dealing was also resented by the Okhrana's longer-serving officers, one of whom anonymously tipped off the Socialist Revolutionaries that the Okhrana had recruited two informers in their ranks, Azef, and a man named Tatarov. Boris Savinkov ordered for Tatarov to be killed: he was stabbed to death on 4 April 1906, but the Socialist Revolutionaries could not believe that Azef was also a spy. Nonetheless, fearing more leaks from within the Okhrana, Azef emigrated to Geneva. He was in Helsinki in February 1906, when he learnt from a go-between named Pinchas Rutenberg that Father Gapon, the