The article examines the history of the urban police of Santiago, specifically its actions to combat the criminality that plagued the Chilean capital of the early 1900s. On the basis of sources like the governorship archive, the press, and police journals, it traces the interactions of the agents and guards of the recently created Fiscal Police with the so-called rateros (pickpockets), and examines their deployment throughout the city streets. The paper suggests that, within the framework of an increasing criminal specialization, the Santiago Police Force was unable to assert its authority. The causes of this were the lack of properly trained personnel, respected by the population, and the close ties of many staff members with the world of crime.