This article says security video footage shows one of the ICE agents shooting at the car as it was driving away from him.

Security footage near the scene in Franklin Park, as reported by CBS News, shows two plainclothes agents approaching a silver sedan that had been blocked from moving by an unmarked SUV. The sedan eventually reverses away from the two agents, and the officer on the passenger side points his firearm at the vehicle.

https://chicagoreader.com/news/ice-shooting-silverio-villegas-gonzalez-franklin-park/