CHICAGO (CBS) — Chicago Police are investigating what led up to an officer pulling the trigger and shooting a teenager Monday night.

CBS 2’s Mai Martinez reports police say the 17-year-old is in serious, but stable condition at a Hyde Park hospital.

The officer says he shot the teen after the teen pointed a gun at him.

“I have to be honest with you, it was a little bit difficult to sleep last night,” said Chicago Police Superintendent Eddie Johnson, addressing the latest Chicago police-involved shooting with concern and relief. “I’m very thankful this situation did not result in a devastating tragedy.”

The shooting happened shortly after 9:30 p.m. Monday. According to Chicago Police, the officer, who was on-duty and in uniform, had just left the Family Dollar store at 79th and Yates after buying water when the 17-year-old walked up to him at his marked CPD cruiser.

“As the officer was entering his car and getting settled, an offender approached him with a gun in hand and a confrontation ensued. The officer was able to un-holster his weapon to fire shots,” Johnson said.

After shooting the teen, the officer notified dispatch about the incident.

“Shots fired by the police at 79th and Yates. Offender in a white t-shirt just fled on foot. Ran up on me and pointed a gun right in my face,” the officer reported to dispatch.

The responding officers took the 17-year-old into custody in a nearby alley and rushed him to the University of Chicago Medical Center.

A Chicago Police spokesman tweeted a picture of a gun officers say was recovered at the scene.

“I can’t tell you all what this young man was thinking, but his actions were clearly very dangerous,” Johnson stated.

Chicago Police say the 17-year-old has a criminal record, but cannot release details because he is a juvenile.

The Civilian Office of Police Accountability (COPA) is investigating the shooting, per protocol. The officer involved has been placed on administrative duties for 30 days.