State Highway Patrol troopers are peicing together just what happened to cause a traffic crash that killed four people in St. Louis this weekend. A mother, her two daughters and a friend died in the crash. A four-year-old survived and is listed in critical condition at a local hospital. The driver of the car, 32-year-old Dorothy McKeller of St. Louis, also survived. The State Highway Patrol says McKeller had been involved in another accident on Missouri Bottom Road near the northbound exit ramp of I-270. Witnesses report McKeller was driving very fast and came up behind an SUV and rammed the rear of it, causing the driver to lose control. The SUV crossed two lanes of traffic and flipped over. The driver survived without serious injury, because he was wearing seatbelts. The patrol says the car sped on and couldn’t make the curve at the end of the exit ramp and went airborne, knocked out an pole, crossed Missouri Bottom Road, struck a second curb and overturned several times. The driver and three passengers were thrown from the vehicle before it struck a building and burst into flames.