Brasília’s former public security chief Anderson Torres has been arrested by Brazil’s Federal Police on his return from the US.
Mr Torres was the capital city’s security chief when rioters stormed Brazil’s Congress, the presidential palace and Supreme Court on Sunday 8 January.
Brazil’s Supreme Court issued an arrest warrant last week, accusing Mr Torres of alleged collusion with rioters behind attacks on government buildings.
Mr Torres denies any role in the riots.
The Supreme Court also accuses Mr Torres of omission – failure to act – in his role as the capital’s security chief.
According to Supreme Court Judge Alexandre de Moraes, Mr Torres’s “omission was amply proven by the predictability of the conduct of criminal groups and the lack of security that enabled the invasion of public buildings”.
In a statement, Brazil’s Federal Police said Mr Torres was arrested as he disembarked at the capital’s airport and taken into custody.
Thousands of protesters – which Brazilian media have described as terrorists and criminals – overran police and ransacked the buildings.
Brazil’s President Luiz Inácio Lula da Silva accused allies of his predecessor Jair Bolsonaro of helping the attack on the presidential palace.
President Lula said people within the presidential palace were complicit in allowing rioters to enter government buildings and he vowed to screen employees to improve security.
Mr Torres – who was Mr Bolsonaro’s former justice minister – insists his conscience is clear.
On Friday, President Lula’s justice minister Flavio Dino said authorities would give Mr Torres until Monday to return to Brazil, or he would face extradition.
Police visited Mr Torres’s home and found a document reportedly trying to reverse October’s election result.
Mr Torres said the document was taken out of context – but did say he would return to Brazil to defend himself, calling last week’s riots the most bitter day of his personal and professional life.
He had been on holiday with his family in Miami when the storming took place, but left on Friday evening to fly back to Brasília.
Following the riots, Brazil’s judicial authorities ordered the arrest of other top public officials and Fábio Augusto, the police commander, was dismissed from his role.
On Friday, the Supreme Court agreed to include right-wing former President Jair Bolsonaro in its investigation of 8 January’s riots.
Mr Bolsonaro, who has refused to concede defeat, posted a video days after the riots questioning the legitimacy of October’s presidential elections, which he lost to Mr Lula.
Prosecutors said the former president may have incited a crime by making such claims.
While the video was posted after Sunday’s riot and later deleted, the prosecutor general’s office argued its content was sufficient to justify investigating Mr Bolsonaro’s conduct beforehand.
Supreme Court Judge Alexandre de Moraes announced Mr Bolsonaro would be included in the probe into what the office of the prosecutor general said was the “instigation and intellectual authorship” of the rioting.
“Public figures who continue to cowardly conspire against democracy… will be held accountable,” Justice de Moraes added.