Brazil's Supreme Court has approved the investigation of far-right former president Jair Bolsonaro's role in the January 8 sacking of government buildings in Brasilia.
The decision on Friday followed a request from the office of the prosecutor general, which cited a video Mr Bolsonaro had posted "questioning the regularity of the 2022 presidential elections" that he lost to former president Luiz Inacio Lula da Siva.
By doing so, Mr Bolsonaro "would have publicly incited the commission of a crime," the PGR said.
Thousands of the former president's supporters, known as "bolsonaristas", invaded the seats of government in Brasilia on Sunday, breaking windows and furniture, destroying priceless works of art and leaving behind graffiti messages calling for a military coup.
The Bolsonaro video was posted online two days after the storming of the presidency, Congress and Supreme Court, and later deleted.
The PGR said that even though the video came after the uprising, it may serve as "a probative connection" that justified "a global investigation of the acts performed before and after January 8, 2023 by the defendant".
Supreme Court Judge Alexandre de Moraes approved Mr Bolsonaro's inclusion in the probe into what the PGR said was the "instigation and intellectual authorship" of the rioting.
In a note seen by AFP on Friday, Mr Bolsonaro's defence lawyers denied any involvement by the ex-president.
Mr Bolsonaro "never had any relationship or participation in these movements," the note said, blaming the violence on "infiltrators".
Mr Bolsonaro had for years sought to cast doubts on the reliability of Brazil's internationally praised election system, and had suggested he would not accept a defeat.
He never publicly acknowledged Mr da Silva's victory, and left for the United States, where he remains, two days before his successor's inauguration on January 1.
As they move to identify the masterminds and financiers of the violent uprising that invited many parallels with the January 6, 2021 storming of the US Capitol, Brazilian authorities have also tightened the screws on Bolsonaro's last justice minister, Anderson Torres.
Mr Torres, who was also in the United States when the riots happened, was arrested early on Saturday on his return to Brasilia.
The Supreme Court had issued warrant against him for alleged "collusion" with the rioters, and he stands accused of "omission" in his most recent job as security chief for the capital. He was fired after the riots.
Brazil's Federal Police said Mr Torres "was arrested upon landing at Brasilia Airport and sent to custody, where he will remain at the disposal of Justice. The investigation remains confidential."
The Folha de S Paulo daily reported that Mr Torres had made an initial court appearance, and was expected to give testimony next week. He was being held at a military police facility.
Mr da Silva's new Justice Minister, Flavio Dino, on Friday confirmed the discovery at Mr Torres' home of a draft decree proposing emergency steps for the possible "correction" of the October election, which Mr da Silva won by a razor-thin margin.
The draft bears Mr Bolsonaro's name, but Mr Dino said the authorship was unknown. It is not known if it was compiled before or after the election.
He said the document connected the dots between Mr da Silva's October 30 election victory and the January 8 riots.
The President and the Justice Minister have both said the violence could not have happened without collusion from members of the security forces.
Mr Torres said on Twitter that the draft had been taken "out of context" to "feed false narratives" against him.
Mr Torres and Mr Bolsonaro have both denied involvement in the January 8 riots.
With reporting from agencies