Two former Och-Ziff Capital Management Group executives, including the ex-head of the hedge fund’s European office, were sued by U.S. regulators over allegations that they spearheaded a sprawling bribery scheme that involved paying tens of millions of dollars across Africa to win business. The Securities and Exchange Commission’s enforcement action against Michael Cohen, who headed the European office, and Vanja Baros, an executive on Africa-related deals, follows a settlement with the U.S. government last year in which an Och-Ziff unit pleaded guilty to violating bribery laws and the firm agreed to pay $415 million.