Brazil's ex-president Luiz Inacio Lula da Silva vowed to battle his opponents in the streets in a defiant speech late Friday, hours after being briefly detained as part of a probe into a massive corruption scheme.
Wearing a red shirt with his leftist Worker's Party yellow star on his chest, Lula gave an emotional speech to supporters where the charisma and feistiness that characterized his 2003-2010 presidency were on full display.
"If they want to defeat me, they will have to face me in the streets of this country!" he told hundreds of supporters at a Sao Paulo rally.
Lula, 70, even shed tears when he talked about how he lifted millions of Brazilians out of poverty during his two terms in office.
Earlier in the day agents took Lula to a police station for questioning, raided his Sao Paulo home, the offices of the Lula Institute, and homes of family members and associates.
Prosecutors said Lula was targeted as part of the Operation Car Wash investigation into a sprawling embezzlement and bribery conspiracy centered on the state oil giant Petrobras.
The corruption scandal, which has already seen a Who's Who of Brazilian politicians and businessmen face charges, is believed to be the biggest ever in Brazil.
Lula was not arrested, but held for questioning over alleged "favours" received from corrupt construction companies implicated in a kickback scheme, prosecutors said.
In a press conference shortly after being released, Lula said the decision to take him forcibly into custody for questioning amounted to "judicial authoritarianism."
"If they wanted to hear from me, they only had to call and I would have gone, because I owe nothing to anyone and fear nothing," he said. "They preferred to show power, arrogance, to make a show."
He was supported by President Dilma Rousseff, a close ally in the ruling Workers' Party, who said she was "in complete disagreement" with the decision to detain Lula.
The drama sent shockwaves through Brazil's already turbulent political landscape.
As officials, backed by camouflaged officers with automatic weapons, went through Lula's house, supporters and opponents demonstrated in the street, shouting and scuffling. Later, as Lula gave his press conference, supporters gathered outside with placards including one that read: "No to the coup."
Lula remains one of Brazil's most influential and powerful figures, and his fate is closely linked to that of his successor Rousseff, and the future of the Workers' Party.
Rousseff, deeply unpopular over her handling of a brutal recession, is already fighting for her political life against the threat of impeachment and a court case that could potentially see her 2014 reelection declared illegitimate.
The risk consultancy Eurasia Group said that "today's detention of ex-President Lula suggests that Rousseff is now unlikely to finish her term in office."
The allegations against Lula focus on a luxury seaside apartment and country house that authorities say appear to have been given to the ex-president as bribes.
"There is evidence that former President Lula received assets arising from the Petrobras scheme through the allocation and renovation of a triplex apartment and a site in Atibaia," prosecutors said in a statement.
Lula denies ownership of the apartment and any involvement in the scheme.
Lula was also accused of receiving about 30 million reais (approximately $8 million) in donations and speaking fees from Petrobras-tainted companies.
"The favours to Lula from big construction companies involved in the fraud at Petrobras were many and hard to quantify," prosecutor Carlos Fernando dos Santos Lima told reporters.
Prosecutors say they are also examining Lula's allegedly wider role in a Petrobras-related web of corruption that enveloped the Workers' Party, the Lula Institute and election campaign finances.
Acknowledging the extraordinary nature of a once hugely popular president being detained, prosecutors said in their statement: "It is not a value judgment about who he is... but an investigative judgment based on facts and certain acts which are under suspicion."
"In a republic, even famous and powerful people must come under judicial scrutiny when there is a well-founded suspicion of criminal activity."
Lula's detention came a day after a bombshell claim by a Brazilian magazine that a former close ally of Lula and Rousseff - a senior Workers' Party senator who has already been charged with Petrobras corruption crimes - was preparing to testify against them.
Senator Delcidio do Amaral, who was arrested last November, was reportedly negotiating a plea bargain deal with prosecutors in which he would testify that Rousseff obstructed the probe and that Lula had also been involved in the scheme.
The report, although unconfirmed, sparked a furious reaction from Rousseff's government.
No allegations have been made officially against Rousseff in the Petrobras scandal.