Brazilian police raided the office of the governing coalition's leader in the Senate, Fernando Bezerra Coelho, on Thursday, part of a wider investigation into a possible kickback scheme.

Investigators said that the personal debts of several officials, including those related to election campaigns, had been paid off by companies that had been awarded public construction contracts.

Police said Brazil's Supreme Federal Court had signed off on 52 search warrants in raids involving more than 200 police officers.

In this May 22, 2019 photo released by the government news agency Agencia Brasil, Senator Fernando Bezerra Coelho speaks during a session at the Senate in Brasilia, Brazil. Bezerra Coelho is one of the targets of a federal police operation into a possible kick-back scheme allegedly carried out when he was in the Cabinet of former President Dilma Rousseff, according to authorities on Thursday, Sept. 19. 2019. (Fabio Rodrigues PozzebomAgencia Brasil via AP)

In this May 22, 2019 photo released by the government news agency Agencia Brasil, Senator Fernando Bezerra Coelho speaks during a session at the Senate in Brasilia, Brazil. Bezerra Coelho is one of the targets of a federal police operation into a possible kick-back scheme allegedly carried out when he was in the Cabinet of former President Dilma Rousseff, according to authorities on Thursday, Sept. 19. 2019. (Fabio Rodrigues PozzebomAgencia Brasil via AP)

Bezerra Coelho's attorney André Callegari said he had not seen the full accusations yet, but that Bezerra Coelho will "obviously deny" any involvement.

Callegari said the investigation also covered the senator's son, also a federal lawmaker.

He called the search "unnecessary" since the investigation targeted events prior to his current role in Congress.

Federal Police leave after searching the office of Senator Fernando Bezerra Coelho, the government leader in the Federal Senate, in Brasilia, Brazil, Thursday, Sept. 19, 2019. Brazilian police say the governing coalition's leader in the Senate is one of the targets of an investigation into a possible kickback scheme. (AP PhotoEraldo Peres)

Federal Police leave after searching the office of Senator Fernando Bezerra Coelho, the government leader in the Federal Senate, in Brasilia, Brazil, Thursday, Sept. 19, 2019. Brazilian police say the governing coalition's leader in the Senate is one of the targets of an investigation into a possible kickback scheme. (AP PhotoEraldo Peres)

Thursday's operation is the result of an investigation launched in 2017, federal police said, predating the administration of President Jair Bolsonaro, who took office on Jan. 1

Authorities are looking into illegal activities allegedly carried out when Bezerra Coelho was a minister in the Cabinet of former President Dilma Rousseff.

His party later dropped its backing for Rousseff and Bezerra Coelho has allied himself with Bolsonaro.

Federal Police stand outside the office, background, of Senator Fernando Bezerra Coelho, the government leader in the Federal Senate, as they agency searches his office in Brasilia, Brazil, Thursday, Sept. 19, 2019. Brazilian police say the governing coalition's leader in the Senate is one of the targets of an investigation into a possible kickback scheme. (AP PhotoEraldo Peres)

Federal Police stand outside the office, background, of Senator Fernando Bezerra Coelho, the government leader in the Federal Senate, as they agency searches his office in Brasilia, Brazil, Thursday, Sept. 19, 2019. Brazilian police say the governing coalition's leader in the Senate is one of the targets of an investigation into a possible kickback scheme. (AP PhotoEraldo Peres)

Federal Police search the office of Senator Fernando Bezerra Coelho, the governing coalition's leader in the Senate, in Brasilia, Brazil, Thursday, Sept. 19, 2019. Brazilian police say Bezerra Coelho is one of the targets of an investigation into a possible kickback scheme. (AP PhotoEraldo Peres)

Federal Police search the office of Senator Fernando Bezerra Coelho, the governing coalition's leader in the Senate, in Brasilia, Brazil, Thursday, Sept. 19, 2019. Brazilian police say Bezerra Coelho is one of the targets of an investigation into a possible kickback scheme. (AP PhotoEraldo Peres)