The Justice Department has launched an investigation into whether Las Vegas Sands Corporation and several of its executives violated money-laundering laws, The Wall Street Journal reported.
Citing unnamed lawyers and other people involved in the matter, the newspaper said the probe was being conducted by the US attorney's office in Los Angeles.
Its investigators want to find out how the casino handled money received several years ago from a Mexican businessman later accused of drug trafficking and a former California executive subsequently convicted of taking illegal bribes.
Sands' chief executive and largest shareholder is hotel and casino industry mogul Sheldon Adelson, whose personal wealth is estimated to be nearly $25 billion.
The Journal said there were no indications that investigators were examining actions by Adelson., a tough critic of President Barack Obama and his policies, who has publicly vowed to do everything possible to prevent his re-election.
Adelson has promised to spend about $100 million this election season to support Republican candidates for president and other elective offices.
Las Vegas Sands spokesman Ron Reese said the company is cooperating with the investigation, The Journal reported.
"The company believes it has acted properly and has not committed any wrongdoing," the paper quoted Reese as saying.