Brazil’s supreme court has opened the trial of politicians accused of ordering the 2018 murder of Rio de Janeiro councilwoman Marielle Franco, a case that exposed deep ties between politics and organised crime in the city.

Franco, an activist who grew up in a favela and became an outspoken critic of Rio’s powerful militia groups, was 38 when she was shot dead in the city center alongside her driver, Anderson Gomes.

The two former military police officers who carried out the murders were given hefty jail terms in 2024.

The supreme court is now trying the former federal lawmaker Chiquinho Brazão and his brother Domingos, a former state lawmaker, accused of ordering the assassination.

The prosecution said their motive had been Franco’s opposition to plans that would have “legalised” land illegally seized by militias that control large parts of the city.

Marielle’s sister, Anielle Franco, Brazil’s minister of racial equality, was present in the packed courtroom as the trial began along with other family members.

It was “unacceptable that a parliamentarian be murdered”, Anielle said before entering the courtroom, adding that those behind the crime must be punished.

Writing in the O Globo newspaper, Franco’s widow, Monica Benicio, said the “criminal ecosystem that killed Marielle continues to operate and extend its tentacles”.

Rio’s militias emerged about four decades ago, when former police officers and security agents created self-defence groups to protect communities from drug gangs.

They quickly evolved into powerful criminal organizations, controlling large parts of the city, extorting residents, seizing public land, and benefiting from high-level political support.

Rivaldo Barbosa, a former police commissioner who first led the investigation, is also being tried for working “to ensure the impunity of those who ordered the killings.”

A former military police officer and a former adviser to Domingos are on trial as well.

The Brazão brothers deny their involvement and have challenged a plea agreement made with Ronnie Lessa, a former military police officer, who confessed to his role in the murder.

Lessa, who was sentenced to 78 years in jail in 2024, said during his trial he was “blinded” and “driven crazy” by the prospect of a million dollar reward for Franco’s murder.

The supreme court trial is being led by justice Alexandre de Moraes, who oversaw the conviction of former president Jair Bolsonaro for plotting a failed coup in 2022.

Moraes said the prosecution’s case did not rest solely on Lessa’s cooperation and that “various pieces of evidence, depositions, and documents” backed up his confession.