NEW YORK (AP) — Wal-Mart Stores Inc. hushed up a vast bribery campaign that top executives of its Mexican subsidiary carried out to build stores across that country, according to a published report. The New York Times reported Saturday that Wal-Mart failed to notify law enforcement officials even after its own investigators found evidence of millions of dollars in bribes. The newspaper said the company shut down its internal probe despite a report by its lead investigator that Mexican and U.S. laws likely were violated.