The Brazilian Supreme Federal Court said Tuesday it was opening a formal investigation into corruption allegations against Sports Minister Orlando Silva. Silva, responsible for organizing the 2014 World Cup, is accused of being involved in kickback schemes through social programs funded by his ministry. He is the fifth member of President Dilma Rousseff's government to be accused of misappropriation of public funds. The newsmagazine Veja has cited a former police officer who accused Silva of taking kickbacks and channeling government money to NGOs linked to his party. Silva called the police officer, who had been in jail for a year, a "delinquent" and warned against what he called a modern inquisition in which people faced accusations without proof. Under rising public pressure in recent months, four ministers for Rousseff -- the first woman elected as Brazil's president -- have already stepped down. Rousseff, who took office at the start of the year, was compelled to launch an anti-corruption drive in July, after several key members of her administration were accused of corruption, including her chief of staff, who was forced to resign in June. Despite the scandals, Rousseff still enjoys 71 percent popularity ratings and is perceived as a leader able to tackle corruption. Agriculture minister Wagner Rossi and transport minister Alfredo Nascimento also had to step down over graft allegations. Tourism minister Pedro Novais was forced to step down amid claims he embezzled millions of dollars. Reports also alleged that he paid a personal assistant with public funds, and his wife used a legislative aide as her personal chauffeur. The mounting scandals come as the country prepares for global scrutiny ahead of the World Cup and Summer Olympics, in what Brazilians had hoped would offer a showcase for its development as a global economic and political force.