BERLIN, Sept. 28 (Xinhuanet) -- All four people aboard an ambulance helicopter died on Wednesday when it crashed in the heavily forested hills east of the city of Stuttgart.

    The pilot, a doctor, a nurse and a sick 28-year-old woman being transported from a hospital in Stuttgart to one in Munich, were all killed in the crash and subsequent explosion.

    Police quoted witnesses as saying that the BK-117 helicopter, which was operated by the Rettungslugwacht company, was clipping treetops as it flew over the area.

    The cause of the accident is still under investigation. Enditem