Police told ABC7 they believed it began when a car pulled up to the front of the school, and someone inside started firing shots toward the school.
Within minutes of the shooting, dozens of police cars and seven ambulances surrounded Dunbar High School. Witnesses say the shooting happened just before 8 p.m. outside the main entrance of the school.
Police said no suspects had been arrested as of 8 a.m. Saturday.
There was a crowd inside the school for a basketball game. When the shooting broke out, it led to chaos.
Some witnesses believe gangs were involved in the shooting. Police say they're unsure whether something happened at the basketball game that may have sparked the violence.
Dunbar was in an overtime game with John Hope College Prep. The paramedics transported five people, all young men, three of them code red at the time. All five were in stable condition Saturday morning.
"More than 200 officers are addressing this problem right now to make sure we've got some good leads going on. We're working closely with the Chicago Public Schools. We're reviewing cameras. We're reviewing any type of film we have to try and get possible leads on this," said Weis.
Police say at this point they have no suspects or motive but they do have a lot of cameras in the area. They are hoping to get some video of some suspects as well as of that car.
None of the injuries at this point are considered life-threatening.