WASHINGTON -- The U.S. Justice Department is investigating whether Las Vegas Sands Corp., owned by high-profile Republican donor Sheldon Adelson, broke federal law by failing to report millions of dollars of potentially laundered money transferred to its casinos by two high-rolling Las Vegas gamblers, according to the Wall Street Journal.

The U.S. attorney's office in Los Angeles is probing deposits made in the mid-2000s by a Mexican pharmaceutical businessman, later indicted for drug trafficking in 2007, and a California executive with Fry's Electronics, who later pled guilty to taking illegal kickbacks, the newspaper said, citing lawyers and federal officials working on the case.

The Journal said there are no indications that the investigation includes actions by Adelson, Sands' CEO and a major political donor for the Republican party. Adelson has pledged to spend as much as $100 million to help Republican candidates in this election cycle.

Federal investigators have begun focusing on casinos amid concerns that the industry's lax financial systems could be used for money laundering and other illegal activities, according to Justice Department officials cited by the Journal.

Sands Corp. did not immediately return calls from The Associated Press on Sunday. A company spokesman Ron Reese told the Wall Street Journal the company believes "it has acted properly and has not committed any wrongdoing."

Chinese-born Mexican businessman Zhenil Ye Gon transferred around $85 million to casinos owned by Sands in the middle of the last decade. He lost more than $125 million at Vegas casinos, according to an affidavit cited by the Journal.

Federal prosecutors say Ye Gon's use of Mexican exchange houses should have been a warning sign of suspicious activity to Sands employees. In July 2007, Ye Gon was indicted in the U.S. on charges of trafficking the illegal stimulant methamphetamine. The drug charges were dismissed in 2009, but Ye Gon is scheduled to be extradited to Mexico to face additional trafficking and laundering charges there.

The Justice Department is also investigating more than $100 million in money transfers by another Las Vegas high roller, Ausaf Umar Siddiqui, who was previously a vice president at Fry's Electronics. Siddiqui was arrested in 2009 for accepting illegal kickbacks. He pled guilty to the charges and is serving a six-year prison sentence.

Las Vegas Sands Corp. owns the Venetian and Palazzo resorts in Las Vegas, as well as similar resorts in Singapore and Macau. Macau is a former Portuguese colony near Hong Kong.

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