LOS ANGELES (CBSLA.com) — An officer-involved shooting in downtown Los Angeles was under investigation Monday after a video of the incident went viral.

Los Angeles Police Department officers were responding to a robbery call around noon Sunday near the Union Rescue Mission, 545 S. San Pedro St., when the incident took place, officials said.

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When they attempted to arrest a homeless man, a scuffle ensued and an officer attempted to use a Taser to subdue him. According to officials, the man then tried to grab for an officer’s gun, which prompted three officers to fire five shots, killing him.

“Right now we know there was a struggle for one of our officer’s weapons,” LAPD Cmdr. Andy Smith said.

A video, which is filled with expletives and could be disturbing to some, was taken by a witness named Anthony Blackburn and posted on his Facebook page.

The sound of a deployed Taser is audible as well as a voice yelling, “Drop the gun,” right before shots are heard.

Another video of the incident has also surfaced, and police say they will review surveillance cameras in the area as well as possible video taken from two of the three officers’ body cameras.

“It’s going to be a long investigation, and we will get to the bottom of it,” Sgt. Barry Montgomery said.

The video taken by the officers will not be released to the public, police said Monday.

L.A. Mayor Eric Garcetti, after being briefed by LAPD Chief Charlie Beck, said he would soon be watching the video.

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“At  this early stage we are still far away from a determination about everything that happened… This will be one element that will strength the investigation but it will not be the sole determinant,” Garcetti stated at a press conference.

Witnesses say the man who was killed went by the name of Africa and had been living in a tent for about six months. They also mention he talked openly about being treated for a mental illness.

A protest was held in Pershing Square Sunday night.

Pastor Wayne Gaddis, who has been working to improve the relationship between the African American community and LAPD, says he understands people’s pain, anger and frustration.

“We do not support police brutality,” he said. “But we do support the police department.”

The three officers involved were placed on paid administrative leave.

Minnie Hedley, President, Los Angeles Branch NAACP, released the following statement Monday: “I am deeply disappointed by the tragic killing of a homeless man by the Los Angeles Police Department yesterday. These homicides committed by police officers in the Los Angeles area seem to have become a weekly occurrence. We remain horrified by the continued use of excessive force we have witnessed at the hands of local police. The Los Angeles Branch NAACP calls on LAPD Chief Beck to institute further training and stiffer penalties for those officers who use excessive force.”

Community leaders have meanwhile called on the Police Commission to hold a special hearing to review the procedures that are used in similar encounters on Skid Row.

Earl Ofari Hutchinson, President of the L.A. Urban Policy Roundtable, said activists would additionally be reaching out to California Attorney General Kamala Harris and California Governor Jerry Brown for independent reviews.

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“We’re calling on Governor Brown today to appoint a special investigator to look at the shooting on Skid Row,” Hutchinson said. “Why? Because we don’t feel confident, based on past performance, that is is going to be thoroughly objective, thoroughly independent, and most importantly, thoroughly impartial.”