By Braden Reddall
The disclosure on Friday comes only months after Halliburton closed the book on the final bribery probe related to $6 billion worth of contracts awarded for a Nigerian project to former subsidiary KBR Inc <KBR.N>.
The Angola-related email arrived in December 2010, and said certain current and former Halliburton personnel violated the U.S. Foreign Corruption Practices Act (FCPA), principally through the use of an Angolan vendor, Halliburton said.
"The email also alleges conflicts of interest, self-dealing and the failure to act on alleged violations of our COBC (Code of Business Conduct) and the FCPA," the Houston-based company said in a Securities and Exchange Commission (SEC) filing.
After advising the U.S. Department of Justice of the probe, which includes assistance from outside lawyers and independent forensic accountants, Halliburton met last quarter with the DOJ and SEC to brief them and provide them documents, it said.
The company described the investigations as "at an early stage" and could not predict their outcome or consequences.
FCPA investigations are not uncommon in the industry. Weatherford International Ltd <WFT.S><WFT.N> has faced four years of scrutiny over its part in Iraq's oil-for-food program, along with its past operations in certain sanctioned countries, including Sudan and Iran.
The DOJ and SEC are probing Weatherford's FCPA compliance and the embezzlement of $175,000 in payments to government officials in Europe, according to company filings.
In 2007, Baker Hughes Inc <BHI.N> settled investigations -- disclosed four years prior -- into its operations in Angola, Kazakhstan and Nigeria, for a total of $44 million.
And last November, The Wall Street Journal reported that industry leader Schlumberger <SLB.N> had investigated bribery charges in Yemen.
(Reporting by Braden Reddall in San Francisco, editing by Matthew Lewis)