An 18-year-old man and two teenage boys — at least one of whom was a CPS student — were shot Monday afternoon near Chatham Academy High School in Burnside on the South Side.

The shooting happened shortly after 4 p.m. as the three teens walked east on 91st Street near Langley Avenue, according to Chicago police.

As they walked, someone got out of a light-colored vehicle and fired at them multiple times, striking all three, police said.

A 16-year-old boy was taken in critical condition to Comer Children’s Hospital with a gunshot wound to his left shoulder, police said. A 17-year-old boy was shot in his left leg, while the 18-year-old was shot in the right arm and left armpit. Both were taken to University of Chicago Medical Center, where the 17-year-old was listed in critical condition and the 18-year-old was in serious condition.

At least one of the teens shot is a student at the school, according to police sources, but it was not immediately clear if all were.

“We’re still investigating that, and we’ll let [Chicago Public Schools] determine if they were students or not,” chief of Patrol Fred Waller said.

CPS officials would not confirm whether the victims are students, but Tony “Qadir” Lyons, the assistant principal at Chatham Academy, told ABC-Channel 7 News that the three did attend the school.

At least one of the teens ran inside the high school after being shot, police said. Two of the victims were found by paramedics at 90th Place and Langley Avenue and the third was found in the 700 block of East 90th Place, according to the Fire Media Affairs.

Lyons told ABC that Chatham Academy students are taught to come back to the school — “a safe haven” in the neighborhood — if they have an issue.

ABC showed overhead video of a victim being taken on a gurney from inside the school to an awaiting ambulance outside. The building was blocked by a line of police tape and officers could be seen going in and out of the school’s east entrance.

The district said it would be providing the school with crisis support staff.

Two suspects were taken into custody after the shooting, police said. They were later released without being charged.

Waller said investigators found only one caliber of shell casings at the crime scene and one gun was recovered as well.

About 2½ hours earlier, a man was shot and critically wounded less than a mile away. Waller said that investigators were working to determine if the two shootings were related.