Brazilian federal law enforcement officials detained former President Luiz Inácio Lula da Silva for nearly four hours to interrogate him on a possible role in the billion-dollar corruption scandal plaguing Petrobras, the nation’s state-run oil corporation.

Reuters reports that law enforcement officials appeared at da Silva’s door early Friday morning, following a tip that the former president had purchased a lavish estate and received cash payments from an extensive kickback scheme in which Petrobras allegedly routinely overcharged for service operations and distributed the illegal profits among its leaders. The New York Times summarized the scandal in August 2015:

Starting in 2004, according to prosecutors, a small number of top Petrobras officials colluded with a cartel of companies to overcharge the oil company for construction and service work. The cartel would decide which of its member companies would win a contract to, for instance, service an oil rig or build part of a refinery. This fake competition was overseen by Petrobras confederates, who were rewarded with bribes.

Da Silva was president of Brazil during the time most of the alleged illegal activity occurred. Dilma Rousseff, his successor, was the nation’s energy minister before being promoted to da Silva’s chief of staff.

Law enforcement estimates that those involved in the corruption scheme made upwards of $3 billion on Petrobras.

Police said of his detention:

Ex-president Lula, besides being party leader, was the one ultimately responsible for the decision on who would be the directors at Petrobras and was one of the main beneficiaries of these crimes. … There is evidence that the crimes enriched him and financed electoral campaigns and the treasury of his political group.

Da Silva was freed after answering questions, and police moved on to interrogating the dozens of others rounded up on Friday morning. Police executed 11 arrest warrants and 33 search warrants on Friday related to the Petrobras scandal.

Brazilian newspaper O Globo suggests that there is evidence, according to police, that some of the Petrobras money made its way into funding political campaigns. It notes that it appears the search warrant that allowed police to detain da Silva was the product of the alleged testimony of Delcídio Amaral, a national legislator, who reportedly claimed he could prove that both da Silva and Rousseff were intimately involved in the Petrobras kickback scheme. Amaral himself has neither confirmed nor denied media reports that he alleged could prove these ties, though those close to da Silva have dismissed the claims. “To get out of jail, he’ll say anything and then won’t be able to prove it,” an attorney close to da Silva told O Globo.

Da Silva himself said in a public statement that his arrest was a “media show,” part of a deteriorating reporting culture in which “pyrotechnics are more important than anything else.” Suggesting he would continue to cooperate with law enforcement, he added, “I should not and do not fear.”

“None of this diminished my honor,” he concluded, “They lit the flame in me and the fight continues.”

Meanwhile, in remarks made at a meeting with Brazilian mayors, Rousseff condemned his interrogation and accused police of “running away with democratic normalcy.”

Da Silva has also received support from neighboring socialist dictator Nicolás Maduro of Venezuela. “Lula, the Path has been long and they have not been able to stop you, you will come out of this miserable attack stronger, Venezuela hugs you,” Maduro tweeted today.