It started as a police car chase in a town in central Louisiana. By the time the pursuit ended, on a dark dead-end street, a 6-year-old boy had been fatally shot in the front seat of a sport utility vehicle.

The Louisiana State Police said Thursday that they were starting an investigation into the death of the boy, Jeremy Mardis, a first grader, in Marksville on Tuesday night. In the last minutes of the boy’s life, he was with his father, Chris Few, who was at the wheel of his S.U.V., apparently trying to elude city marshals who wanted to arrest him.

The state police said in a statement that the marshals opened fire on the S.U.V. at the end of the pursuit, about 9:30 p.m., and that the driver was critically injured and a 6-year-old passenger was dead. A state police spokesman, Scott Moreau, did not identify the occupants of the vehicle.

One of the first people called to the scene was Dr. L.J. Mayeux, the coroner of Avoyelles Parish. In a telephone interview, he named the driver as Mr. Few, who had been in the vehicle with his son, Jeremy.