As Paul Volcker put the finishing touches last week on his final report on the U.N.'s role in the oil-for-food scandal, investigators continue to uncover details about Kojo Annan's links with Cotecna, the company at the center of the influence-peddling inquiry. In late 1998, U.N. sources say, Kojo, son of U.N. Secretary-General Kofi Annan, got a $3,000 loan from a friend for a down payment on a sporty green Mercedes ML 320 in Geneva, Switzerland. The friend was Michael Wilson, then a vice president of Cotecna, the firm that not only employed Kojo but also won millions of dollars in...