Police shoot man after witnessing Humboldt Park homicide

CHICAGO -- Chicago Police shot and injured a man overnight, after witnessing a homicide in the Humboldt Park neighborhood.

Officers were on routine patrol at Division Street and Maplewood Avenue around 11:30 p.m. Friday, when they witnessed two men arguing.

Investigators say the men were both shooting at each other.

One of the men was struck and killed by the other man.

Officers acted quickly, and shot the man believed to be the gunman.

No officers were injured.

The Independent Police Review Authority is investigating, as it does all police-involved shootings.

The officer or officers involved in the shooting will be put on administrative leave, which is the police department's policy.

The man who was fatally shot, has not been identified.

This story is developing, check back for updates.