A years-long probe of Goldman Sachs's ties to Libya's sovereign wealth fund is focusing on an internship and other perks allegedly offered by the Wall Street bank to win business from the Gadhafi regime, according to people familiar with the matter.

The Securities and Exchange Commission is reviewing the New York-based bank's decision in June 2008 to hire as an intern the brother of Mustafa Zarti, then deputy chief of the Libyan Investment Authority, the people said. The move came after Goldman entered into more than $1 billion worth of trades with the authority, and just as the firm's relationship with the Libyan fund had begun to sour.