Mark Kelley, 52, was charged with felony impersonation of a police officer and misdemeanor aggravated assault with a deadly weapon. View Full Caption DNAinfo; Chicago Police Department

UPDATE: Kelley pleaded guilty in July 2015 to a downgraded charge of misdemeanor reckless conduct, court records show. Cook County Judge Catherine M. Haberkorn sentenced Kelley to community service, $349 in fines and one year of court supervision.

COOK COUNTY CRIMINAL COURTHOUSE — Prosecutors said a CPS teacher ran a car off the road Thursday, pretended to be a cop and shouted expletives — only to find out the driver was a real police officer.

West Ridge Elementary teacher Mark Kelley, 52, forced another car off the road near Irving Park and Pulaski roads on Thursday, Assistant State's Attorney Erin Antonietti said during a bond hearing Friday.

When Kelley got out of his car, he yelled "I am a police officer from Wisconsin, and I am going to f--- you up," according to a police report. Kelley proceeded to snap photos of the victim's car and drove off.

The victim, an off-duty Chicago police officer, flagged down a beat car a few blocks away, the report said. The officer was able to identify Kelley, who had a knit cap, glasses and a CPS paycheck in his car, according to the report.

Kelley, of the 4100 block of North Francisco Avenue, was charged with felony impersonation of a police officer and misdemeanor aggravated assault with a deadly weapon, for using his car to allegedly force the other vehicle off the road.

On Friday, Cook County Judge Laura Sullivan ordered Kelley released on his own recognizance.

A police report lists Kelley's occupation as a teacher at West Ridge Elementary, 6700 N. Whipple St.

For more neighborhood news, listen to DNAinfo Radio here: