CHICAGO — Video released Tuesday by a civilian oversight agency shows an off-duty Chicago police officer shooting an unarmed, autistic man during an incident initially described as an armed confrontation.

Sgt. Khalil Muhammad shot then-18-year-old Ricardo Hayes as he walked on the city's South Side. Hayes had wandered away from his home around 5 a.m. on Aug. 13, 2017, according to a lawsuit over the shooting filed by the American Civil Liberties Union. His caretaker called police, informing them he was autistic.

The grainy home security video released by the Civilian Office of Police Accountability shows Hayes running along a sidewalk before stopping. Muhammad then stops the SUV he's driving and gets out. Hayes takes a few steps toward the vehicle before Muhammad shoots him in the arm and chest.

The video shows Hayes running off despite his wounds. Now 19, he has recovered from his injuries.

"As a black teenager with disabilities, Ricky was at a heightened risk for police violence," said Karen Sheley of the ACLU of Illinois said in a statement. "Thankfully, he survived - but he should never have been shot."

At the time, police officials described the incident as an armed confrontation.

"The video shows both that there was no justification for the officer to shoot him and that initial stories told by CPD officials about the shooting — that the 'encounter escalated' — were false," Sheley said.

The sergeant's call to 911 was among the audio files released.

"The guy, like, he was about to pull a gun. Walked up to the car, and I had to shoot," Muhammad told a Chicago Fire Department dispatcher. Police Superintendent Eddie Johnson later said Hayes had no weapon.

The initial assertion of a confrontation mirrors statements by police after the 2014 fatal shooting of 17-year-old Laquan McDonald. Jason Van Dyke was convicted earlier this month of second-degree murder and aggravated battery in the slaying. Despite video to the contrary, Van Dyke and other officers on the scene claimed McDonald was acting aggressively before the shooting.

In a statement, COPA said its delay in releasing the Hayes video and related material was due to concerns about the legality of releasing of information related to wards of the state.

Chicago police spokesman Anthony Guglielmi said Tuesday that Muhammad is on administrative leave pending the outcome of the COPA investigation.