The Chicago Police officer who fatally shot an unarmed man on the Northwest Side was stripped of his police powers Tuesday.

The 57-year-old officer, assigned to the mass transit unit, was off duty when the shooting happened about 9:15 a.m. Monday in the 2500 block of North Lowell, according to police.

Jose Nieves, 38, died from multiple gunshot wounds, and his death was ruled a homicide, according to autopsy results released Tuesday by the Cook County medical examiner’s office.

Police spokesman Anthony Guglielmi announced Tuesday evening that CPD Supt. Eddie Johnson had stripped the officer of his police powers.

“As part of the ongoing investigation of the fatal shooting on the 2500 block of North Lowell, this afternoon Superintendent Eddie Johnson has relieved the officer involved in the incident of his police powers,” Guglielmi said in an email. “The Chicago Police Department continues our fact-based investigation of the incident, in parallel with the Independent Police Review Authority.”

Nieves did not have a weapon, Guglielmi said.

“I have a lot more questions than I do answers at this time,” Johnson had said during a briefing with reporters Monday. “I came out because I wanted to make sure that the investigation was done properly.”

Johnson said the officer does not live in the area and knew the person he shot from another “confrontation a few weeks ago.”

An “altercation” between the men escalated and the officer shot him several times, according to a police statement. Nieves was taken to Illinois Masonic Medical Center, where he died at 9:51 a.m., authorities said. His home address was unknown and members of his family could not be reached Tuesday.

The police department and Independent Police Review Authority have opened simultaneous investigations into the shooting.

Dean Angelo Jr., president of the Fraternal Order of Police Lodge 7, said Tuesday that he had not seen any reports associated with the shooting and that he’d refrain from commenting further.

Investigators were canvassing the area for witnesses and any surveillance footage, according to police. The shooting happened on the same block as Kelvyn Park High School.

Asked Tuesday if investigators had contacted the school for security footage, a CPS spokesperson referred questions to police.

Court records show Nieves had been arrested more than 20 times on charges that including domestic battery, theft, burglary and assault. He was convicted only once, in 2012, on charges of marijuana possession and possession of a replica gun. He was sentenced to court supervision.

Siclaly Mandujano, 16, and her family have lived a half block south of the shooting scene for five years and was at home when she heard three shots fired. She said she hears gunfire in the area at least once a month.

She sat on her front porch, holding her dog, a Chihuahua-Jack Russell terrier-poodle mix, named Lucky, as police closed off traffic on the block.

“I have two older brothers and it’s kind of dangerous for them,” Mandujano said. “They’re not in anything bad or anything, but it’s dangerous for them.”

Contributing: Jordan Owen