The shootout killed a police officer and 27 others in Jacarezinho on Thursday (May 6). Police said it was the deadliest operation in Rio state since a 2005 raid on the city's northern outskirts.
Rio's police are among the most deadly in the world, but right-wing President Jair Bolsonaro has argued that if anything they need fewer restrictions on lethal force.
"They (suspects who died) were to hand themselves over and the police came in and killed them. The police came in and killed. They killed (my son)," said Adriana Santana Araujo, 36, mourning the loss of her 23-year-old son.
Daniele dos Santos said her 32-year-old husband had gone out to buy bread and was caught in the crossfire.
Police said everyone killed, except for the officer, were suspected drug traffickers reacting violently to police presence.