NEW : Parents of the two girls who arrive in San Francisco . NEW : Asiana Airlines ' management spoke to the parents during their arrival in Seoul . Ye Mengyuan and Wang Wei , both 16 , both died after the crash . One of the girls killed may have been hit by a vehicle .
NEW : Parents of the two girls killed arrive in San Francisco . NEW : Asiana Airlines ' CEO apologized to the parents during their layover in Seoul . Ye Mengyuan and Wang Linjia , both 16 , both died after the crash . One of the girls killed may have been hit by emergency vehicle .