[post_page_title]The cover up[/post_page_title]
The head of Walmart de Mexico would hide the bribes by saying that they were standard legal fees when he would submit invoices to Walmart International. However, a high ranking Walmart de Mexico manager whistle blew to Walmart International which promptly started an internal investigation.
However, the investigation was soon ended, and officials allegedly tried to sweep everything under the rug. That is, until a whistle blower went to The New York Times with the story.