A worker for the city of Chicago who was putting a Denver boot on a vintage auto was shot in the back after a confrontation with the car's owner.

Police spokeswoman Monique Bond says the Department of Revenue worker was in serious condition in Northwestern Memorial Hospital after the attack Monday in the South Chicago neighborhood.

Investigators say they are looking for the car's registered owner after the victim identified him as his attacker.

Bond said police recovered three .22-caliber shell casings believed to be from the gun used in the crime.

According to police, there has been a spike in violent crime in the South Chicago neighborhood. As a result of gun violence, the district has the city's highest murder rate so far this year.

Click here for more on this story from MyFOXChicago.