Witnesses, who did not want to speak on camera, told ABC7 they heard multiple gunshots in a Country Club Hills neighborhood.
They reported seeing one person with a ski mask running through the neighborhood followed by a massive law enforcement response.
Officials with the ATF, the FBI, and Country Club Hills police, along with neighboring police departments, including those in Hazel Crest, Flossmoor, Midlothian, and Chicago, all responded.
ABC7 saw multiple crime scenes in the area, with the largest being on Loretto Lane near 189th Street, where investigators were surrounding a white vehicle. It is unclear how that vehicle is involved.
A couple of blocks away, ABC7 saw more investigators at Martin Lane and Martin Court. Those investigators focused on a black Mitsubishi.
COPA said a Chicago police officer was involved, but did not elaborate.
ABC7 reached out to Chicago police and they referred us to ATF, who is handling the investigation. The ATF said the investigation is ongoing.
Authorities did not immediately say whether anyone was injured.
What led up to the shooting was not immediately clear.
COPA asked anyone with information to call 312-746-3609 or visit https://www.chicagocopa.org/.
Officials did not immediately provide further information.