At least six cars, including an Illinois State Trooper's squad, were hit by rocks tossed onto the outbound Eden's Expressway early Friday morning.
One of three people who were throwing rocks from an overpass and striking vehicles on the outbound Edens Expressway earlier Friday has been arrested and is being held without bond, authorities said.
Kevin Houlihan, 18, was charged with illegal consumption of alcohol by a minor and criminal trespassing on railroad property. Two others are being sought, police said, adding that they have good leads on who they're looking for.
No one was hurt in the incident, which was initially reported as gunfire striking a vehicle, but one of the vehicles hit by rocks was a squad car of an Illinois State Trooper.
A motorist called shortly after midnight to report that the vehicle he was driving was struck by gunfire on the northbound Edens Expressway near Peterson Avenue, according to Illinois State Police District Chicago Trooper Ivan Bukaczyk.
When troopers rushed to the area, the windshield of one squad car was cracked when it was struck by something, which turned out to be rocks, Bukaczyk said.
A total of six cars were hit, Pfotenhauer said.
Rock debris was discovered on the roadway and investigators learned the rocks were being thrown from an overpass about 1/8 of a mile north of Lawrence Avenue.
Pfotenhauer said the incident should serve as a reminder to drivers to stay attentive when they're behind the wheel.
"You really have to know what's around you. Please don't just focus on the vehicle in front of you. You've got to know what's next to you, what the overpass is that you're approaching, so that you just don't focus in and have tunnel vision when you're driving," she said.