Nothing But the Night (1973)

Three trustees of the Van Traylen fund have died during the last few months in deaths looking like suicides. However, after a mysterious bus accident involving the last three trustees and thirty orphan kids, Police Colonel Bingham (Sir Christopher Lee) starts investigating. The first question is why the bus driver, killed in the accident, is burnt when there was no fire during the accident. Dr. Ashley (Peter Cushing) uses hypnosis to find the truth about the mysterious happenings.