In a newly released audio message, al Qaeda leader Ayman al-Zawahiri claims that his organization is holding hostage Warren Weinstein, a 70-year-old American who went missing last August in Pakistan. Zawahiri's statement is the first official claim of responsibility by any group in relation to the kidnapping, and a U.S. official said the statement buttressed earlier "indications" that al Qaeda might be holding the American. "I tell the captive soldiers of Al Qaeda and the Taliban and our female prisoners held in the prisons of the crusaders and their collaborators, we have not forgotten you and in order to free...