Detroit ? A gunman stepped out of a sport utility vehicle and shot four teenagers on a primary-school lawn near their Detroit high school shortly after class let out Thursday, killing one of them, police said.

Three teenagers were arrested at their homes about five hours after the shooting near Henry Ford High School, Deputy Police Chief James Tate said. The male suspects are 15, 16 and 18, and the 16-year-old is a student at the high school, Tate said.

One suspect and one victim had fought earlier in the day at the school, he said.

Christopher Walker, 16, was pronounced dead at Providence Hospital, a spokesman said. He was an 11th-grader at Henry Ford, said a Detroit Public Schools spokesman.