The cellphone’s trail led from bloodstained Fallouja to the engineering school here, a modern campus where researchers in white coats stroll past labs and the breeze rustles through trees in courtyards dotted with pine cones. Two years ago French investigators, aided by U.S. intelligence, detected calls from Iraq to a central figure in a suspected extremist cell in Montpellier. French intelligence officials say the calls came from a militant leader in Fallouja involved in the grisly killing of four American military contractors by a mob on March 31, 2004, an incident that became an icon of the savage conflict in Iraq.Full Story