This is a book about the St. Petersburg Detective Police, about the history of its creation, about high-profile crimes of the past and their detection, about how the noble business of investigation developed from the time of the establishment of a separate organization in the 60s of the 19th century until its transformation into Petrograd Metropolitan Criminal Investigation Department in 1917. But most importantly, this is a book about people, about those who served in the Detective Police and will tell true stories about it, which are based on previously practically unpublished materials, including the secret archives of the Detective Police and III Department of His Imperial Majesty's Own Chancellery, Security Department, rare memories of eyewitnesses and participants in the events.