Zubatovite trade unions achieved moderate success at channeling workers' political agitations away from revolutionary movements and toward labor improvements, especially in the cities of Minsk and Odessa, with one high-ranking official noting that many revolutionaries and workers were joining the unions. However, Zubatov, if not police socialism, became discredited in the summer of 1903 after the Okhrana officer in charge of the Odessa union allowed a strike to get out of hand, causing a mass movement which paralyzed the region. Although the police-run unions continued to operate after Zubatov's ousting, without Okhrana funding, they proved more a liability than an asset. The Assembly of Working Men, a police-run union with about 6,000–8,000 members, formed by the alleged Okhrana agent Father Georgy Gapon, sparked the Bloody Sunday massacre of January 1905, a milestone in the Revolution of 1905 when union members marched peacefully on the Winter Palace in St. Petersburg and were fired upon by Imperial soldiers. The Okhrana complemented police socialism and other projects to prevent the conditions in which revolutionary movements could take hold by pursuing initiatives to curtail the activities of existing organizations. Yevno Azef, the notorious Okhrana provocateur who became the head of the Socialist Revolutionary Fighting Organization (SRFO), epitomized the Okhrana's inscrutable practice of revolutionary-group infiltration. While the Okhrana managed to imbed many of its agents in revolutionary organizations, the police preferred to slowly gather intelligence and to attempt to interfere with revolutionary work surreptitiously rather than to arrest known revolutionaries immediately. This policy led to numerous dubious acts on the part of police spies, who needed to participate in revolutionary activities to avoid suspicion, as when Yevno Azef, as head of the SRFO, ordered the assassination of V. K. Plehve on July 15, 1904.