Brazilian President Dilma Rousseff's former campaign strategist, Joao Santana, was arrested in Sao Paulo after returning to Brazil to face allegations that he received payments linked to funds from a massive corruption network.
Prosecutors are investigating USD 7.5 million in payments to Santana in foreign bank accounts.
The funds were connected to Brazilian construction giant Odebrecht and engineer Zwi Skornicki, who have both been implicated in a huge probe into embezzlement and bribery at state oil company Petrobras.
Santana arrived in Sao Paulo from the Dominican Republic, where he had been working for President Danilo Medina's reelection campaign.
He and his wife and business partner Monica Moura were then immediately flown in police custody to Curitiba, the southern city where the Petrobras-related corruption is headquartered.
His arrest is an embarrassment to Rousseff and her fellow Workers' Party predecessor Luiz Inacio Lula da Silva, just two of the many presidents in the region that Santana has helped elect.
The country's electoral court is investigating whether Rousseff benefited from illegal funding in her 2014 reelection. She also faces an impeachment drive in Congress over her government's allegedly illegal accounting practices during her first term.
Odebrecht is one of the key players in a network where bribes were paid to Petrobras to win lucrative contracts.
Kickbacks were then allegedly used to pay off prominent politicians in a scheme estimated to have cost Petrobras some USD 2 billion over a 10-year period.
Rousseff chaired the company's board during much of that time. She has not been directly accused in the scandal, but it has ensnared top leaders of her Workers Party.
Santana is a campaign star in Latin America, having also worked for Venezuela's late president Hugo Chavez and his successor Nicolas Maduro, among others.
A police spokesman in Curitiba said that Santana would be held in detention for up to five days.
"In principle, that can be extended or transformed into preventative detention," he said.
Prosecutors say there are "clear indications" that the funds paid to Santana originated in stolen Petrobras money.
However, his lawyers say that any money paid to Santana abroad was for work done outside of the country.
