Sheldon Adelson, the billionaire casino magnate, has been the leading contributor to outside groups supporting Mitt Romney and other Republican candidates this election cycle, donating tens of millions of dollars. His company, Las Vegas Sands, is also the focus of a federal investigation into possible violations of bribery laws at its casinos in Macau, China.

In an interview with Politico published Sunday night, Adelson drew a link between his donations and the investigation, arguing that he has been targeted because of his political activity. A victory for Obama, he said, would bring government "vilification of people who were against" the president, including himself.

Adelson's company has been under investigation since at least early 2011, when the SEC subpoenaed company documents in connection with the possible bribes.

Adelson has given to Republicans since the 1990s. But he started spending big on the presidential race in January 2012, when he and his wife, Miriam, wrote a pair of $5 million checks to Winning Our Future, a super PAC that supported Newt Gingrich's campaign.

Las Vegas Sands did not immediately return a request for comment on Monday.

Both federal and Nevada investigators are looking into some of the tactics Adelson's company used to build an elaborate casino complex in Macau, the world's gambling capital. ProPublica and Frontline have reported that Adelson told a company executive to pay $700,000 in legal fees to Leonel Alves, a Macau public official whose firm served as an outside counsel and who met with local officials on Las Vegas Sands' behalf.

Las Vegas Sands' general counsel at the time, J. Alberto Gonzalez-Pita, warned at the time that the payments to Alves could violate the Foreign Corrupt Practices Act, which makes it illegal for American companies to bribe foreign officials. It is unclear whether Adelson was aware of his general counsel's warning. Gonzalez-Pita later resigned.

In the Politico interview, Adelson accused the government of trying to discredit him by leaking information about the investigations. (The New York Times and The Wall Street Journal have also run stories about the investigations.) The idea, Adelson told Politico, is to make "me toxic so that they can make the argument to the Republicans, 'This guy is toxic. Don't do business with him. Don't take his money.' Not all government employees are leakers, but most of the leakers are government employees."