Updated

Tearful friends, family and admirers gathered in Rio de Janeiro on Thursday to pay homage to a black city councilwoman who was gunned down one year ago in a brazen slaying that has sparked nationwide outrage.

Marielle Franco and her driver, Anderson Gomes, were killed in central Rio on the evening of March 14, 2018 while returning from an event focused on empowering young black women.

Authorities this week arrested two former police officers for the murders, but the case continues to highlight deep corruption in Brazil and there are unanswered questions about who ordered the hit and why.

"It is my worst nightmare to be participating in the mass paying homage to my assassinated daughter," said Franco's father, Antonio Francisco da Silva Neto, at a commemoration service.

Vigils, lectures and protests were also planned for Franco in Stockholm, Buenos Aires, Madrid, Bogota, Lisbon, Berlin, London and several cities in the United States.

In Rio de Janeiro, some placed flowers in a line of vases, lit candles and demanded accountability with a banner that read "Justice for Marielle and Anderson."

Commemorations then continued with a service at a Catholic Church in downtown Rio, where followers of Afro-Brazilian religions wore traditional white garb, sang chants, and held signs reading "Marielle is present" and "For black mothers."

Franco's mother, Marinete da Silva, said her daughter had "become a symbol of resistance all over the world."

Many also took to the streets to celebrate black, female politicians who won post during October elections. Several of them had been on Franco's staff.

Elected in 2016, Franco was a member of the left-leaning Socialism and Liberty Party and was known for her work in shantytowns and her outspokenness against police violence, which disproportionately affects black residents in a country where more than 50 percent of people identify as black or mixed-race.