SEYNE-LES-ALPES, France (AP) — The heads of Lufthansa and its low-cost airline Germanwings are visiting the site of the crash that killed 150 people amid mounting questions about the co-pilot and how much his employers knew about his mental health. German prosecutors say Lubitz's medical records from before he received his pilot's license referred to "suicidal tendencies," but visits to doctors since then showed no record of any suicidal tendencies or aggression against others.