A 16-year-old boy was killed and another teenage boy was in custody after allegedly trying to rob an off-duty Chicago police officer at gunpoint Thursday morning in the Arcadia Terrace neighborhood on the Northwest Side.

At 2:23 a.m., the CPD officer was sitting inside his personal vehicle parked in the 5800 block of North Talman Avenue when the two teens walked over, CPD Deputy Chief Al Nagode said in the press conference after the shooting. The 16-year-old allegedly pointed a handgun and announced a robbery.

The officer handed over his belongings, Nagode said, but the second boy reached in the car and patted the officer down for more items.

He located a second wallet that contained the officer’s police star, Nagode said. The 16-year-old allegedly pointed his gun at the officer and told him not to move.

“The officer, knowing that he’s armed, was forced to pull out his weapon, and he fires at the individual,” Nagode said.

After he shot the 16-year-old, the other boy ran away with the officer’s belongings, Nagode said.

“Not having a phone on him now, the officer begins to shout, asking for help,” Nagode said. “Our neighbor comes out and responds, [telling] him that he needs an ambulance.”

After emergency responders were called, the 16-year-old was brought to St. Francis Hospital in Evanston and pronounced dead shortly after.

The Cook County medical examiner’s office identified the boy as Sarge Junior, who lived in the West Rogers Park neighborhood on the North Side.

Assisting police units soon caught the boy who fled the scene and placed him under custody, Nagode said. Charges were pending Thursday morning.

The officer was parked alone in that block after going to a movie theater with two friends, Nagode said. He had his head down when the two teens approached his vehicle.

Police said the officer is a 32-year-old man who has been with the department for six years. He is assigned to the Major Accidents Investigation Unit.

The 16-year-old boy’s stepfather reported the teen went missing with his weapon Wednesday night, Nagode said. The weapon recovered at the scene matched the description his stepfather provided.

The Civilian Office of Police Accountability was investigating the use of force by police and the officer involved will be placed on administrative duties for 30 days, police said.

It was the second officer-involved shooting over the past two days. On Tuesday morning, a CPD officer took a bullet to the vest in an exchange of gunfire that wounded another person in the South Side Gresham neighborhood.