American authorities investigating the killing of Wall Street Journal reporter Daniel Pearl in Pakistan now believe that he was slain by the hand of Khalid Shaikh Mohammed, the alleged mastermind of the Sept. 11 attacks. Authorities, who had previously cast doubt on reports of Mohammed’s role, now have new information that leads them to believe he killed Pearl, said one U.S. official who spoke on the condition of anonymity. The official declined to detail the evidence. The U.S. acknowledgment of Mohammed’s suspected role was first reported in Tuesday’s editions of the Journal. Pearl, the Journal’s South Asia bureau chief, was abducted on Jan. 23, 2002, while working on a story on Islamic militants in Karachi. Full Story