Updated

Authorities say an SUV driver pulled up alongside a car in southern Wisconsin and opened fire, killing a 5-year-old boy.

Police are searching for the person responsible for the Friday night attack in Beloit, a city 65 miles southwest of Milwaukee along the Illinois border.

Interim Police Chief David Zibolski says the maroon SUV had been following the boy's father's car, but that he doesn't know if the father was the intended target. He says the father is cooperating with investigators.

Zibolski says detectives haven't determined how many shots were fired. The boy was shot at least once in the abdomen and died at Beloit Memorial Hospital.

Police are asking anyone with information about the attack to come forward.