A Facebook Live video has captured the despair of a woman who said her brother was shot by police several times in a suburb of San Diego, California on Tuesday.

The black man, who is yet to be formally identified, has died, authorities said.

Friends of the man's family have told the San Diego Tribunehe suffered from a "mental illness."

The livestream, posted to Facebook by Rumbie Mubaiwa, shows a woman wearing what appears to be hospital scrubs. She cries that she called for help many times, but when police arrived, they shot her brother.

"I just called for help, and you came and killed him," she said, as bystanders try to comfort her. "Why couldn't you guys tase him? Why, why, why, why? I told you he was sick."

In a statement, the El Cajon Police Department said officers were called shortly after 2 p.m. to Broadway, El Cajon by reports of a man "not acting like himself." The man, who they identify as an African American man in his 30's, was walking in traffic.

An officer asked the man to remove his hand from his pocket, and drew his weapon when the man did not comply.

A second officer arrived and "immediately prepared to deploy a less lethal electronic control device" or taser.

The man took an object from his pocket and assumed "what appeared to be a shooting stance," police said. At that point, both officers discharged simultaneously. One with a firearm, striking the man, one with his taser.

The man was taken to an area hospital and has died.

A witness captured the incident on video and turned their phone over to investigators voluntarily, police said. Police also said the man did not have his hands up when he was shot, according to a video, although other witnesses have contradicted this.

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In an interview with NBC 7 reporter Ashley Matthews, a witness said he saw a black man surrounded by officers with their guns out. The witness said the man had his arms out, spread-eagled from his body when facing police.

"He's jerking, he's confused, he runs this way, and as soon as he runs this way, they discharge," the witness said. "Boom, boom, boom."

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Another woman in Mubaiwa's video said the man did have something in his hand but it wasn't a gun.

"I said: 'Take your hand out your pocket, baby, or they're going to shoot you.' He said 'no, no, no,'" the woman said. "When he lifted his hand out ... he did have something in his hand but it wasn't no gun, and that's when they shot him."

Police did not say if any weapon was recovered from the scene.

Shortly after the incident, crowds of protestors began to gather shouting "Black lives matter" and "Hands up don't shoot."

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Police and the District Attorney's Office are investigating the fatal encounter.

According to police, the two officers will be placed on administrative leave at the conclusion of the investigation per El Cajon Police Department policy.

The shooting comes soon after the deaths of two other black men at the hands of police. Terence Crutcher was fatally shot in Tulsa, Ok. on Sept. 16. Keith Lamont Scott died after being shot by police in Charlotte, N.C., on Sept. 20.

Police have since released footage of the incidents in both Tulsa and Charlotte. According to NBC 7, El Cajon police are set to order body cameras but they aren't yet in use.

The cellphone video of the shooting won't be released as it forms part of the investigation, El Cajon Chief of Police Jeff Davis said.

This story is developing.