A 16-year-old boy was shot and killed early Thursday by an off-duty Chicago police officer who the teen was trying to rob on the Northwest Side, police said.

Another teen also was part of the robbery attempt; he fled, but was caught.

The stepfather of the 16-year-old who was killed had reported him missing — along with the stepfather’s weapon — Wednesday night, according to CPD Deputy Chief Al Nagode. A weapon recovered at the scene matched the description his stepfather provided.

The robbery and shooting occurred about 2:20 a.m. in the 5800 block of North Talman Avenue. The officer was sitting in his personal vehicle in the Arcadia Terrace neighborhood when the teens approached, Nagode told reporters at the scene.

After the 16-year-old pointed a handgun at the officer, Nagode said, the officer handed over his belongings. Then, the second boy reached into the car and patted the officer down.

That teen found a second wallet that contained the officer’s CPD star, Nagode said; the 16-year-old then 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 the officer shot the 16-year-old, the other boy ran away with the officer’s belongings. Other officers soon caught him, Nagode said.

The 17-year-old boy was charged with a felony count of armed robbery with a firearm and two misdemeanor counts of theft, police said. He was expected to appear in juvenile court on Friday.

“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.”

The 16-year-old was brought to St. Francis Hospital in Evanston, and was pronounced dead shortly after arriving. He was identified as Sarge Junior, with a last known address in West Rogers Park, according to the Cook County Medical Examiner’s office.

An autopsy Friday found that Junior died from multiple gunshot wounds. His death was ruled a homicide.

Gilda Sebeck lives one block east with her husband, John Sebeck, a retired Chicago police officer. She said the gunshots woke her up.

She knows the officer’s parents, who live on that block of Talman, she said.

They are “lovely people … the kind of people you’d want to have as neighbors,” she said. “This neighborhood is a good neighborhood. We look out for one another.”

The officer was parked alone 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 32-year-old officer has been with the department for six years. He is assigned to the Major Accidents Investigation Unit.

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.

COPA urges anyone who has information about the incident, or witnessed the shooting, or has video of the incident, to call them at 312-746-3609.

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.

Another neighbor, Britt-Marie Harding, said she also was awakened by the first gunshot. Then she heard two more — and after that, screaming.

The stretch of Talman where the shooting occurred is lined with neat bungalows on both sides of the block.

“This street is really quiet. Really, the whole neighborhood,” Harding said.

She was afraid to look out because she didn’t know who was shooting. Detectives came to question her at 4 a.m., she added.

It wasn’t until later in the morning that she saw the blood on the sidewalk in front of a neighbor’s house.

“It’s horrible,” she said later Thursday, with the sidewalk still wet from where the neighbor had hosed off the blood.

“I feel so sad for everyone involved.”