LOS ANGELES -- Three Los Angeles police officers fired at and killed a man on the city's Skid Row during a struggle over one of the officers' guns, and authorities said they planned to use video captured by a bystander in their investigation.
The graphic video widely circulated on social media within a few hours of the incident Sunday brought heightened attention to the death of the man who wound up wrestling with police amid the tents, sleeping bags and trash of Skid Row, where many of the city's homeless stay.
The three officers, one of whom is a sergeant, shot the man as they struggled on the ground for control of one of the police officer's weapons, after a stun gun proved ineffective, LAPD Cmdr. Andrew Smith said. They were answering a report of a robbery.
Even hours after the shooting, tensions in the area remained high, reports CBS Los Angeles.
Smith said the department was aware of the video, and would attempt to amplify its sound and pictures to figure out exactly what happened.
"The video is disturbing," Smith said at a briefing with reporters late Sunday night. "It's disturbing any time anyone loses their life. It's a tragedy."
Smith said at least one of the officers was also wearing a body camera.
On the video, six officers can be seen responding to the scene, and they begin wrestling with the man as he takes swings at them.
Two of the officers break away to subdue and handcuff a woman who picked up one of their dropped batons.
The struggle becomes increasingly blurry and distant, but shouting can be heard, including the word, "gun," followed by five ringing gunshots.
Police did not release the man's name or give any other identifying details, and Smith said he did not know whether the man was homeless.
Witnesses told the Los Angeles Times that the man is known on the street in the area as "Africa," and that he had been there for four or five months.
Witness Yolanda Young told CBS Los Angeles the suspect was in a tent arguing with another man and that he then began struggling with officers.
"Next thing I know, dude swung on a cop and the cop swung back," Young said. "And they were hitting on him and then two other cop cars pulled up and they got out of the car and ran over there, and they had three tasers out."
One witness, Jose Gil, 38, told the Times he saw the man swinging at police, then heard one of them shout, "He's got my gun!" before the shots were fired.
Dennis Horne, 29, said the man had been fighting with someone else in his tent before officers arrived.
"It's sad," Horne said. "There's no justification to take somebody's life."
Tents and cardboard shelters cover the sidewalks of Skid Row, the downtown neighborhood where an estimated 1,700 homeless people live. Many of them struggle with mental illness and addiction.
Police Commission President Steve Soboroff said the independent inspector general and the district attorney had all begun investigating the incident.
Earl Ofari Hutchinson, head of the activist group the Los Angeles Urban Policy Roundtable, called on the Police Commission to hold special hearing on use of force by officers in Skid Row encounters.
Hutchinson said in a statement that the shooting "underscores the need for the police commission to hold a special hearing to fully examine police tactics and training in the use of deadly force by LAPD officers involving skid row residents many of whom have major mental challenges."
The violence Sunday had echoes of the August shooting by Los Angeles police of 25-year-old Ezell Ford, whose death in a struggle with officers brought demonstrations in the city.
Ford was unarmed, but police officers said he was shot only after reaching for an officer's gun.