The head of Brazil’s National Force for Public Security, Col. Adilson Moreira, has resigned, citing his disgust with the ongoing corruption scandal engulfing the administration of President Dilma Rousseff. The resignation leaves security operations for the 2016 Summer Olympics in Rio de Janeiro mostly unmanned until Rousseff names a replacement.

Moreira tendered his resignation Thursday, with Brazilian news outlets reporting that shortly before stepping down, he had sent an email to relevant parties, strongly condemning Rousseff’s socialist Workers’ Party (PT) and the president personally.

“The government is not interested in this country, but in holding on to power at any cost,” the letter reportedly read. Moreira wrote, “My family demands this of me, as one does not have to be too intelligent to know that we are being managed by an unscrupulous group, including the president of the Republic.”

“I feel more and more ashamed. What were once rumors are now concrete,” he lamented.

The “rumors” in question are allegations that Rousseff was aware of a billion-dollar kickback scheme at Petrobras, the state-run oil corporation. Rousseff was the nation’s minister of energy while officials were allegedly overcharging contractors for Petrobras projects and pocketing the difference. The president at the time, Luiz Inácio Lula da Silva, has been questioned for having direct involvement in the operation. Shortly after being questioned by police regarding the scandal, Rousseff appointed da Silva her chief of staff – a job she also held during his presidency. The appointment grants da Silva executive immunity from the court investigating Petrobras.

Argentine news outlet Infobae notes that the Brazilian Justice Ministry has issued a statement in which it called the accusations in the letter “very grave,” and, should the letter be proven legitimate, Moreira may have committed “a gesture of administrative disloyalty,” a disciplinary infraction.

The Wall Street Journal notes that Rousseff must now find someone to replace Moreira to organize the relevant force’s 10,000 police officers, to be deployed to protect Olympics sporting venues in August.

Moreira is the third high-ranking official to resign in the wake of evidence that ties Rousseff to the Petrobras scandal. All three held pivotal jobs for this summer’s Olympics: Minister of Sports George Hilton and Minister of Tourism Henrique Alves.

In his resignation statement, Alves, a member of the minority Brazilian Democratic Movement Party (PMDB), lamented that his party was “standing before the greatest challenge of choosing its path” and that “dialogue [with the Workers’ Party] has been exhausted.”

Hours after Alves resigned, the PMDB voted to part with the Workers’ Party, forcing all PMDB officials who were appointed to govern under Rousseff to resign. The move also frees PMDB legislators to vote to impeach Rousseff, threatening to end Rousseff’s tenure early. Rousseff faces impeachment for financial infractions independent of the Petrobras scandal.

Rousseff’s popularity decreased significantly following evidence released that indicates she purposely appointed da Silva her chief of staff to keep him from facing justice. Federal Court Judge Sergio Moro released the tapes in March of a conversation between da Silva and Rousseff in which she guarantees him a cabinet post “in case of emergency.” Rousseff has called the release of the tape a major error and the impeachment process an attempt at a “coup.” Brazilians appear to disagree, however, as her disapproval ratings, according to a poll released last week, are currently at 82 percent.

On Thursday, Moro – who has become a popular hero among those supporting Rousseff’s ouster – was stripped of his power to oversee the case. Brazilian newspaper O Globo reports that the Brazilian Supreme Court made the move, an institution seen to have a favorable disposition towards Rousseff. Even with his executive immunity, the Supreme Court could approve of the opening of a case against da Silva, though Rousseff in wiretaps appeared confident this would not occur. O Globo cites a criminal lawyer describing the move to keep Moro away from the case as an attempt to “rebalance the game” in Rousseff’s favor.