A Black man was killed Tuesday night in a police-involved shooting on the city's West Side. Police were called to Monticello and Division following a report of an argument and a man with a gun running down the street. Police say sergeant who arrived at the scene shot the man in self-defense. "You point a gun, you put somebody in peril of their life, they're … gonna shoot," said police spokesman Pat Camden. Camden said a sergeant fired his service revolver at a man who pointed his gun at him. The man in his 20s was running down an alley. "The sergeant chases him through the alley, into the alley. He turns, pulls the gun. He's in a crouched position, putting the sergeant in a defensive light posture. The sergeant fires, the offender is killed," Camden described. Maurice McBride said he witnessed the shooting. McBride said the young man threw something on the ground when he ran away before the shooting started. "He didn't have no gun. Whatever he threw, he threw. I feel that's unjustified and they're out here protesting like it's justified. That's not right," he said. The scene was heated Tuesday night. Witnesses say the man was shot in the back. Police say the man was shot in the chest and a .45 caliber semi-automatic gun was found in his hand. Family members at the scene say their cousin was the man killed and that he was unarmed. They also say a number of people were running and someone yelled that someone had a gun, but it wasn't their cousin. The family members still maintain the man was shot in the back. The man was taken to Mount Sinai Hospital, where he was pronounced dead, Camden said.  Police recovered a .45 caliber semi-automatic weapon from the man, as well as four tin-foil packets containing a substance suspected of being cocaine, Camden said. [MORE]