( Read More: Wal-Mart's Staffing Levels Criticized Over Not-So-Fresh Groceries ) Meanwhile, groups that often complain about Wal-Mart's business practices on Monday asked for the removal of Duke and Chairman Rob Walton, a son of deceased founder Sam Walton, from the board. The United Food and Commercial Workers International Union and its OUR Walmart subsidiary said that letters were sent to Wal-Mart's global ethics office calling for Wal-Mart's board to remove Duke and Rob Walton "for their failure in leadership in preventing the alleged bribery, trying to cover it up" and not taking meaningful action to fix internal problems. The letters were dated April 22, which coincided with the anniversary of the publication of The New York Times report.