RIO DE JANEIRO (AP) — Brazilian protesters have taken to the streets of Rio de Janeiro by the thousands to demand answers in the slaying of a city councilwoman who was a prominent human rights activist, Marielle Franco.

Demonstrators stretched banners across some of the city's iconic landmarks and spray-painted walls with slogans such as "Fight like a Marielle."

Saturday's protests come a month after Franco and her driver were shot dead. The activist had been critical of a security force takeover of policing in Rio and many of her backers have called the slaying a political assassination.

Authorities say surveillance footage shows two vehicles followed Franco's car and they are trying to trace fingerprints from shell casings found at the scene.

Franco's sister and the wife of driver Anderson Pedro Gomes joined the march.