It was only a matter of time. Obama administration officials say they will probe whether Pakistani authorities helped hide Osama bin Laden, a day after the al Qaeda leader was found and killed in a mansion located in the same town as the country's top military academy. John Brennan, President Obama's top counterterrorism adviser, said it was “inconceivable” that bin Laden didn't have a significant “support system” there. Sen. Carl Levin, chairman of the Senate Armed Services Committee, said the Pakistani army and intelligence agency have “a lot of questions to answer.” They'll have to be somewhat tactful about asking them, however. U.S.-Pakistani relations have been especially tense over CIA action in the country and recent drone strikes. And Pakistan, both nuclear-armed and home to Islamist militants, is still vital to U.S. security interests. Secretary of State Hillary Clinton made sure to thank "all of our partners around the world, including Pakistan, who have helped us put unprecedented pressure on al Qaeda."