Mark Thatcher & Simon Mann's African Coup

Weeks after the Senate report was made public, the Security and Exchange Commission's Fort Worth office notified four of America's largest oil companies that they were the subject of a preliminary investigation in connection with violation of securities laws prohibiting bribes to foreign government officials.

The firms are Amerada Hess, ChevronTexaco, ExxonMobil and Marathon, all with roots in Texas. The SEC has plenty of deals to pore over.

For example, oil firms have paid $4 million to fund the education aboard of about 100 Equatorial Guinean students, most of them relatives of Obiang and his closest advisors. Another potential source of bribery was the $1 million in leases the oil firms paid for property and buildings owned by relatives of President Obiang, according to federal investigators. An ExxonMobil official told Senate investigators last summer that this was business as usual in such banana republics.

"It may be virtually impossible to do business in such countries without doing business with a government official or a close relative of a government official," said Andrew Swiger, an Exxon executive vice president.