French Experts Hunt for Argentina Helicopter Crash Clues

French and Argentine investigators scoured the charred wreckage of two helicopters in a rugged region of western Argentina on Thursday for clues to what caused an in-flight collision that killed 10 people, including three French sports stars. The head of Argentina's investigation team promised a meticulous investigation into Monday evening's accident, which killed Olympic swimmer Camille Muffat, yachtswoman Florence Arthaud and boxer Alexis Vastine. Amateur video of the crash shot from the ground showed the two helicopters flying at low altitude when one veered into the path of the other, its rotors appearing to clip the railings or tail of the other helicopter.