CHICAGO (CBS) — Rocks pierced the front windshield of a Chicago Police squad car Tuesday night, and a sergeant was hospitalized with minor injuries.

The incident happened just before 9 p.m. on Cermak Road just west of Western Avenue in Little Village.

Initial reports indicated that someone had fired bullets and pierced the squad car windshield, but police later clarified that the damage was done by rocks thrown from an overpass by three people.

A sergeant suffered a minor cut to her arm from the shattered windshield and was taken to an area hospital in good condition, police said.

Three people were taken to the Ogden District station for further investigation, police said.

Area Central detectives are investigating.