The company said in the past 10 days, its lawyers uncovered notes written between 1993 and 1998 that suggest consortium executives discussed bribes to secure a multibillion-dollar natural-gas liquefaction plant on the Nigerian coast, beginning in January 1996 and still ongoing.
Halliburton said it has turned over the evidence to investigators in the United States, France and Nigeria, who already had been investigating the consortium, the Wall Street Journal said.
The company did not release names or positions of those involved.
Halliburton said it is unclear from the newest documents whether money actually was paid. When the notes were written, Nigeria was ruled by military dictator Sani Abacha, and the company was run by U.S. Vice President Dick Cheney. It was unclear if Cheney was aware of the discussion.
"There is no way to read these materials and not be concerned about that," says James Doty, an attorney with Baker Botts LLP, a law firm brought in by Halliburton this year to examine the matter.