US Secretary of State Hillary Clinton has said, she believes that al-Qaeda chief Osama bin Laden and Taliban chief Mulla Omar are still in Pakistan. In a Television interview in Islamabad she said, it will be very helpful if they are caught.Though the Pakistani leaders claim that the world's most wanted terrorist may be dead, top US officials have been maintaining that bin Laden along with his powerful deputy Ayman al-Zawahiri are in Pakistan.