Authorities are looking for a gunman who shot a Contra Costa College police aide.

Police say the 19-year-old aide was shot Thursday afternoon after confronting a man he believed was a car theft suspect.

When the suspect ran from the campus, the aide radioed for police and chased him in a motorized cart.

A Richmond police spokesman says after leaving the campus, the gunman turned and fired several rounds at the aide, hitting him at point blank range.

The victim was taken to a regional trauma center, where he was listed in critical but stable condition.

His name has not been released.

The shooting prompted college officials to lock down campus buildings for about an hour.