A baby and his 17-year-old mother were killed in a single-car crash in Charles County last night, and Maryland State Police were looking into reports that the vehicle was speeding alongside a second vehicle just before the wreck.

The mother and her 7-month-old boy were reported dead at the scene in the Newburg area, south of La Plata. Police identified them early today as Rachel S. and Thomas D. Townsend of Waldorf.

Two unidentified girls ages 14 and 15 who were also in the vehicle were flown to a hospital with unspecified injuries, police said.

The white Mazda was headed south on Route 301 near Edgehill Road during a downpour when it ran off the road about 6:30, said Cpl. Eric Diggs. The car overturned down an embankment, ejecting Townsend, who was driving, police said. Thomas, who was in a car seat, was not thrown from the car.

Several cars stopped to help, Detective Sgt. Ronald Best said. Police said they believed that speed, driver error and weather conditions were contributing factors in the accident.

Officers were reinterviewing witnesses late last night to confirm reports that a second vehicle had been seen speeding alongside the Mazda. Traffic at the nearby intersection with Edgehill might have affected witnesses' perceptions, Best said.