Jair Bolsonaro has been taken into custody after authorities found he posed a concrete flight risk while under house arrest.
The ex-president was convicted of plotting a military coup in September and sentenced more than 27 years in prison, but he remained under confinement pending appeals.
Brazilian Supreme Court Justice Justice Moraes said the move to detain the elderly politician was a preventative measure after fresh information emerged.
This included seeking to disable his ankle monitor and a summons to a demonstration that could facilitate a chance to flee".
Legal Document Reveals Flight Fears
In a filing authorising the detention, Justice Moraes said intelligence from the facility tracking Bolsonaro's house arrest suggested the one-time head of state's "intention to break the surveillance device to ensure success in his escape.
This, it said, would be made easier by the disorder caused by the protest called by his child.
His offspring, Flávio, who serves as a legislator, called for a gathering of his followers near his father's house to take place on the weekend.
His son wrote on online platforms on Friday: "Are you going to fight for your nation, or observe everything from your smartphone there on your sofa? I call on you to battle with us."
He said the gathering would be so backers could offer prayers for his physical condition and for the reestablishment of democratic governance in our nation."
Diplomatic Refuge Fears
Part of the judge's decision was the chance of his "relocation to embassies near the dwelling, considering that the probes revealed a history of organizing to request asylum through a embassy office", a statement said.
The court filing emphasizes that the United States embassy in the federal district, Brasilia, is located around 13km from his dwelling.
Worldwide Consequences
His judicial problems have provoked anger from fellow conservative nationalist US President Trump, causing him to impose a fifty percent tax on goods coming from Brazil.
The former president is being kept in a Federal Police station in Brazil's capital city and will undergo a imprisonment assessment on the next day.
Recent Legal Requests
It was only on last Friday that the former president's lawyers asked the High Court to authorize him to fulfill his full incarceration period under domestic detention, with electronic monitoring.
They also asked that the former president be allowed to leave his home for medical treatment, saying he needed ongoing care for respiratory ailments and other ailments.
Details of Guilty Verdict
He was convicted of heading a conspiracy aimed at keeping him in power after he lost the presidential race to his left-wing rival, Lula.
Top judicial officials said that he had knowledge of a plot which encompassed plans to assassinate Lula and his VP candidate, Geraldo Alckmin, and to detain and kill Justice Moraes - the top judicial official who has been managing Bolsonaro's trial.
The conspiracy was prevented because it failed to get the backing of the military leaders. Lula was inaugurated without incident on January 1st, 2023.
But a seven days after, on 8 January, many his backers stormed and vandalised government buildings in the capital, Brazil's capital.
The police took action and around fifteen hundred individuals were detained.
The judges found that the demonstrators had been incited by the former president whose scheme, they said, was for the Brazilian military to intervene, bring back stability and reinstate his authority.
At the moment, Bolsonaro's lawyers called the 27 years and three months sentence extremely harsh.
He was also prohibited from campaigning for office until 2060 - eight years after the completion of his term.
The ex-leader called the legal proceedings a political persecution and said it was aimed at blocking him participating in the 2026 national vote.
