Complexo do Alemão massacre
The Complexo do Alemão massacre was the result of an ongoing conflict between drug dealers and the police in the borough of the same name in Rio de Janeiro, which consisted of a group of large favelas in the northern region of the city. The massacre happened on June 27, 2007, when a large Military and Civil Police operation killed 19 people and injured several others.
Source: Wikipedia — Complexo do Alemão massacre (CC BY-SA 4.0)