Jonathan Williams was pronounced dead inside the gym at McDonogh High School after the shooting about 10:30 a.m., police Capt. Marlon Defillo said. The student was hit "multiple times," according to the spokesman.
A 15-year-old girl wounded in both legs was in serious condition. One 16-year-old girl was wounded in the left thigh and a second 16-year-old girl in the left arm and buttocks. They were both in good condition at Charity Hospital.
About 200 students were in the gymnasium when four suspects entered the building, Defillo said. Only two of them were armed, one with an AK-47 assault rifle and a second with a semi-automatic pistol.
"The victim was apparently seated on the bleachers with other students when the gunmen confronted him," the police officer said. "They began firing multiple gunshots at the teenager, striking him multiple times."
Stray bullets hit the girls as they tried to flee.
Police quickly arrested four teenagers for questioning in the shooting spree. Three suspects -- ages 17, 18, and 19 -- were found hiding in a house after a car chase. A fourth subject, 15, was found hiding under a house.
Defillo said they were being questioned and no criminal charges had been filed as of late Monday.
Police found an AK-47 assault rifle in a nearby yard and a semi-automatic pistol underneath a house.
Several students and residents interviewed by WDSU-TV speculated that the shooting might be gang-related.
The school was locked down for about 90 minutes after the shooting and at noon parents were allowed to pick up their children.