In Sao Paulo, hundreds of people have been marking the 20th anniversary of a prison massacre in which 111 inmates at the Carandiru gaol were killed.
The establishment held 10,000 prisoners in 1992, when a riot began with a row between two prisoners over a football match. It soon developed into a fight between rival gangs. When police tried to restore order, critics accuse them of killing indiscriminately as they shot prisoners at point- blank range.
Some inmates were said to have been killed by police dogs, and an evangelical pastor described his own escape as a miracle. The commander of the raid was convicted for using excessive force in 2001, but acquitted on appeal five years later. Soon after he was found dead in his flat.
Now dozens more police are due to face charges relating to the operation, though officers have always claimed they were obeying orders. Carandiru was closed and demolished in 2002, but Brazil still has half a million people in prison, the fourth biggest total in the world.