The impeachment proceedings against Brazilian President Dilma Rousseff have put a spotlight on endemic corruption in the ranks of lawmakers. Some 60 percent of the 594 legislators in both chambers of Congress are being investigated for wrongdoing or are facing corruption charges, according to watchdog groups. Many of the investigations are related to a kickback scheme at state oil company Petrobras. The three men in line to replace Rousseff if she is impeached are themselves being investigated in the Petrobras and other cases.

FIRST IN LINE: Vice President Michel Temer.

— A former senator turned state's witness recently accused Temer of appointing a lobbyist to distribute bribes between 1997 and 2001 in ethanol deals through Petrobras. He denies wrongdoing.

— Temer is accused of arranging the appointment of a Petrobras director who was involved in a series of corruption cases linked to Temer's Brazilian Democratic Movement Party. He denies knowing the man.

— As acting president, Temer signed the same kind of budget decrees that triggered the current impeachment process against Rousseff. Detractors have already signaled they may try to impeach him based on those actions.

— Temer is being investigated for receiving more than US$ 1.5 million in funds from a construction company that works with Petrobras. Temer says they were legal campaign donations.

— Authorities seized spreadsheets from construction company Camargo Correa that showed Temer's name listed 21 times alongside numbers that added up to $345,000, allegedly in bribes. While the case was thrown out in the courts, the investigation is credited with having led to the current Petrobras probe.

SECOND IN LINE: Chamber of Deputies Speaker Eduardo Cunha.

The speaker, an evangelical who frequently tweets biblical verses, would be the de facto president when Temer is traveling abroad or if he becomes incapacitated. Cunha is being investigated in several corruption cases. He denies wrongdoing in all of them.

— Brazil's chief investigator has requested the Supreme Court remove Cunha from office because of all the allegations of wrongdoing against him and for allegedly obstructing justice. The court has not yet made a decision.

— In March, prosecutors accused Cunha of corruption and money laundering for his role in negotiating contracts for drill ships, including a payment of $5 million.

— Swiss prosecutors say Cunha owned secret bank accounts at Julius Baer bank. In December, those accounts had 2.4 million Swiss francs, according to local reports. Brazilian investigators say they believe those funds are connected to corruption with a Petrobras oil field operation in Benin.

— Brazilian investigators say Cunha also has held undeclared accounts in the United States since 1990, with funds of more than $20 million.

— A senator-turned-government-witness said Cunha and the Brazilian Democratic Movement Party were paid more than $10 million by BTG Pactual bank to get an executive order approved by the lower house.

— In court testimony from a lobbyist who plead guilty in the case, Cunha is accused of being paid bribes worth more than $12 million from constructors Odebrecht, OAS and Carioca to renovate Rio's port area ahead of the Olympic Games.

THIRD IN LINE: Senate leader Renan Calheiros.

Calheiros would be acting president in the case that both Temer and Cunha were traveling abroad or incapacitated. Brazil's Supreme Federal Tribunal is currently considering seven investigations against Calheiros in the Petrobras probe. He denies wrongdoing in all. Included in those seven are:

— Calheiros is accused by a lobbyist of being paid $600,000 to stop a Senate probe of corruption in Petrobras.

— Calheiros is accused by a former Petrobras director of threatening to withhold support unless he was paid off. The same ex-director says Calheiros was paid $1.7 million through a Petrobras lobbyist in a case related to drill ship contracts.

— In a plea bargain, another former Petrobras director accuses Calheiros of using lower Chamber of Deputies representative Anibal Gomes to be pay bribes for contracts with constructors.