The emails contradict earlier claims by Wal-Mart senior executives that they weren't aware of bribes being made by the company.
Democratic Congressmen Elijah E. Cummings of Maryland and Henry A. Waxman of California, who are investigating bribery charges at Wal-Mart's Mexico division, Thursday released emails that indicate that Duke and other senior Wal-Mart officials were informed multiple times starting in 2005 about bribes being made in the country. U.S. law forbids American companies from bribing foreign officials.
The lawmakers shared the emails, which they say they got from a confidential source, with Wal-Mart on Wednesday, and sent a letter to Duke asking for a meeting to discuss them.
"It would be a serious matter if the CEO of one of our nation's largest companies failed to address allegations of a bribery scheme," according to the letter written by Waxman and Cummings to Duke.
Allegations first surfaced in April that Wal-Mart failed to notify law enforcement that company officials authorized millions of dollars in bribes in Mexico to speed up getting building permits and gain other favors. Wal-Mart has been working with government officials in the United States and Mexico on that investigation.
The company also has been conducting an internal investigation into the matter. And last November the retailer said in a filing with the Securities and Exchange Commission that it was looking into potential U.S. bribery law violations in Brazil, China and India.
Brooke Buchanan, a Wal-Mart spokeswoman, issued a statement Thursday saying Wal-Mart has been providing information to the Department of Justice and the SEC, including the documents released by the lawmakers. The world's largest retailer also said it is exploring other ways to make additional information available.
"We are committed to having a strong and effective global anti-corruption program everywhere we operate and taking appropriate action for any instance of noncompliance," Brooke said.