The shooting of a West Side man Monday night by a Chicago police officer has sparked outrage and led to a near riot in the Lawndale community where the shooting took place.

Aaron Harrison, 18, was fatally shot in an alley near Mozart and Fillmore streets around 8 p.m. Monday by a Chicago police officer. Police said Harrison pointed a 9mm semi-automatic gun at the officer.

Police News Affairs said patrolling officers observed Harrison standing in front of a grocery store at Francisco and Roosevelt Road with a group of men, holding his waist and “acting unusual,” according to published news accounts. When officers approached, Harrison, according to police, took off down an alley.

According to police, the uniformed officer chased after Harrrison and ordered him to drop his weapon, but Harrison allegedly turned and pointed his weapon at the officer. Police said Harrison was shot in the shoulder in self-defense. Harrison was pronounced dead at the scene around 9 o’clock Monday night, according to the Cook County Medical Examiner’s Office.

On Tuesday, the medical examiner’s office ruled that Harrison died from a gunshot to his back, according to an autopsy report released by the office.

The shooting resulted in a near riot as residents in the neighborhood disputed police accounts of the shooting.

About 100 people marched on the Harrison District Police Station, 3151 W. Harrison, just hours after the shooting late Monday.

One person was reportedly arrested during the ruckus where bottles were thrown at officers. Additional police had to be summoned to the area.

Police, according to news accounts, physically held some in the crowd back, and a local newspaper cameraman covering the event reportedly had one of his cameras destroyed by police and another one thrown by officers.

According to news accounts, witnesses and members of Harrison’s family said he did not have a weapon and called the shooting unjustified. Witnesses and family said Harrison was not involved with gang or drug activity and was a member of a hip-hop dance group.

Residents and community leaders have called for an investigation and said Monday’s shooting was another example of police brutality and young black men in the community being targeted by police.

The police department’s Office of Professional Standards is investigating the shooting and the alleged incident involving the cameraman.