The operation, dubbed Purification, began in the early hours of the day in Duque de Caxias, in the outskirts of Rio de Janeiro.

BBC: Latin America & Caribbean

The police commander in Duque de Caxias, Claudio de Lucas Lima, has been sacked, but there is no indication that he was involved in the wrongdoing.

BBC: Latin America & Caribbean

The case last September of a teacher from Rio's violent Duque de Caxias suburb who was stabbed after reprimanding pupils for drug-dealing was by no means exceptional.

ECONOMIST: Start at the beginning

Prosecutors say the policemen were paid to overlook criminal activities in 13 slums of Duque de Caxias, a populous working class city that is part of Greater Rio de Janeiro.

BBC: Latin America & Caribbean