He didn’t do it. The Saudi national questioned in the aftermath of the Boston Marathon terror blasts that killed three is considered a witness rather than a suspect, sources told the Daily News on Tuesday. RELATED: BOSTON MARATHON BOMB DEVICES WERE PRESSURE COOKERS FILLED WITH NAILS, BALL BEARINGS: REPORT Abdulrahman Ali Alharbi, 22, remained hospitalized in Boston as investigators searched every inch of his Revere, Mass., apartment and grilled his roommate. But it turns out the student was apparently in the wrong place at the wrong time when two bombs exploded Monday afternoon near the finish line of the event...