Casino magnate Sheldon Adelson, the biggest Republican donor in the 2012 election, has come under new scrutiny for possible violations of federal anti-bribery law and ties to Chinese organized crime. The potential violations stem from Adelson’s efforts to build casinos and other projects in Macau. An investigation by the University of California, ProPublica and PBS Frontline found Adelson may have violated the Foreign Corrupt Practices Act when he instructed a top executive to give $700,000 to a Macau legislator who aided his company’s efforts there. Officials are also probing possible ties between Adelson’s company, Las Vegas Sands and Chinese organized crime. The projects in Macau helped Adelson amass a personal fortune estimated at $25 billion. He has given tens of millions of dollars to Newt Gingrich, Mitt Romney and other Republican causes, and has spoke of spending upwards of $100 million to defeat President Obama’s re-election.