At 13:20 on the last Friday in September, 1989 a frantic call was received at the local police station. There had been a serious automobile accident at the intersection of Main Street and State Street with injuries involved. Lt. John Henry arrived at the scene ten minutes after the phone call and found that two cars had collided at the intersection. In one car, the driver was unconscious and in the other car, both the driver and one passenger were injured. After the emergency vehicles transported the injured to the hospital, Lt. Henry's responsibility is to investigate the accident in order to determine whether one of the drivers (or both) are responsible. With the severity of injury in this accident, the investigation is critical because there may be a fatality involved.