Two influential Brazilian politician brothers have been convicted by Brazil’s supreme court of ordering the murder of Marielle Franco, the Rio de Janeiro city councillor, nearly eight years ago.

João Francisco Inácio Brazão, the former congressman known as Chiquinho, and the former adviser to Rio’s court of auditors Domingos Inácio Brazão were sentenced to 76 years and three months in prison for the murders of Franco, 38, and her driver, Anderson Gomes, 39.

The crime was one of the most shocking and high-profile murders in Rio’s history and drew international attention: Franco, a gay Black woman, was a rising political star and an outspoken critic of police violence and corruption.

The justices’ decision was unanimous, and the Brazão brothers were also convicted of the attempted murder of Fernanda Chaves, Franco’s press officer at the time, who was in the car and survived.

The case is also widely seen by security experts and human rights activists as a chilling example of how the ties between politics, crime and the police are deeply entrenched in Rio, reaching even the highest levels of public administration.

Franco’s sister, Anielle Franco, wrote on social media: “It was eight years of struggle to find out who ordered Marielle’s killing and why. It was eight years fighting for full justice.

“Today Brazil’s justice system honoured the memory of Marielle and Anderson. Brazil begins a new historic chapter in confronting political violence based on gender and race. Impunity cannot be part of our democracy,” added Anielle, who is minister for racial equality in the government of Luiz Inácio Lula da Silva.

Announcing her vote, Justice Cármen Lúcia said the proceedings had been “very painful” for her.

“Human justice is not capable of soothing this pain. This trial is merely a timid, almost embarrassed testimony on my part of the response the law can offer in the face of the searing, atrocious pain borne on the faces of the mother, the daughter, the son, the widows,” added Lúcia, referring to the relatives of Franco and Gomes, who were present in the courtroom.

The long journey of almost a decade to secure the convictions was marked by a tortuous series of twists that included the destruction of evidence, frequent changes in lead investigators and even the revelation that the then head of the homicide division, Rivaldo Barbosa, actively worked to obstruct the investigation.

Barbosa was not convicted of murder on Wednesday, as the justices found there was insufficient evidence that he had taken part in the killings, but he was found guilty on the lesser charges of obstruction of justice and corruption for having received bribes from the Brazão brothers.

The case was tried by the supreme court because Chiquinho was a congressman when his involvement was uncovered. The convictions came more than a year after two former police officers who carried out the killings were sentenced by a court in Rio.

Ronnie Lessa, who fired the shots in the drive-by shooting, and Élcio de Queiroz, who drove the getaway car, were sentenced in October 2024 to decades in prison, but their sentences were reduced to a maximum of 30 years after they confessed and cooperated with investigators.

Lessa, regarded as one of Rio’s most ruthless hitmen, said he had been hired by the Brazão brothers – long accused of involvement with paramilitary mafia groups known as militias – to kill Franco after becoming frustrated by her efforts to disrupt lucrative housing development schemes.

“Marielle Franco became a highly significant obstacle to the economic and political interests of those who ordered the crime,” said the rapporteur, Justice Alexandre de Moraes.

One of the most profitable activities of the militia led by the Brazão brothers was the illegal occupation of land – much of it in environmentally protected areas – followed by property development and the provision of services such as electricity and internet.

Franco, who at the time served alongside Chiquinho on Rio’s city council, was a vocal advocate for housing rights and frequently warned residents not to join new illegal projects created by the militia.

“Marielle Franco was a Black, poor woman who was confronting the interests of militiamen,” said Moraes. “What stronger message could they send? In the misogynistic, prejudiced minds of those who ordered and carried out the killing, who would care about this [her murder]?”

The Brazão brothers’ lawyers focused their defence on attempting to discredit Lessa’s confession, arguing that there was no other evidence of their involvement in the crimes. However, all the justices agreed that, beyond the testimony, there was “abundant evidence” to support their convictions.

Two former police officers were also convicted: Ronald Paulo de Alves Pereira, for monitoring Franco’s routine in the days leading up to the crime; and Robson Calixto Fonseca, known as The Fish, who will answer only for armed criminal organisation for having delivered the murder weapon to Lessa.

Jurema Werneck, executive director of Amnesty International in Brazil, said the convictions were “a fundamental milestone, a chance to turn the page in the history of Rio and Brazil”.

“First, because it affirms the need to protect human rights defenders. Fighting for rights cannot cost lives … Second, this decision also marks a turning point in the fight against impunity, so that crimes like this are not repeated,” she said.