This page explains what went on in the Imperial Palace between Max Payne and the Crachá Preto
War On The Crachá Preto
Da Silva drops Max off near the Imperial Palace Hotel, The Cracha Preto's hideout and front building. Once in the hotel, Max finds a group of kidnapped civilians in a room, and releases them from their captivity. One of the people he releases is Serrano, now a beaten and "pathetic" man.
Max fights his way through the hotel until he finds a morgue inside the building, where he confronts Arthur Fischer, a doctor and one of the men behind the body harvesting. Fischer begs for his life and offers money to Max. Serrano soon interferes and confronts the doctor for his crimes, ultimately killing him as Max leaves the scene.