Updated

A purported conversation captured on a YouTube video apparently shot in the immediate aftermath of the fatal police shooting of Michael Brown has a possible witness saying the unarmed 18-year-old charged at the officer who fired the shots that have led to more than a week of sometimes violent demonstrations in the St. Louis suburb of Ferguson.

Amid angry condemnations of the police and pledges to move away from the mean streets of Ferguson, one man describes what he saw as he witnessed the shooting. He seems to describe how the 6 foot, 4 inch, 300-pound Brown tussled with Police Officer Darren Wilson and charged him, an account that may corroborate Wilson's story and cast doubt on claims of other purported witnesses who say Wilson shot Brown as he ran away, his hands in the air.

EXTREMELY GRAPHIC CONTENT: This YouTube video contains disturbing images and audio content, which should be considered before viewing

"I mean, the police was in the truck [sic] and he was, like, over the truck," the man says. "So then he ran, police got out and ran after him.

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“The next thing I know, he comes back towards them. The police had his guns drawn on him."

The graphic, 10-minute video, which has been viewed nearly 1 million times on YouTube, begins with the camera operator walking toward the street where Brown's body can be seen lying on the pavement on the other side of yellow police tape. The reliability of those heard speaking cannot be verified, but Ed Magee, spokesman for the St. Louis County Prosecutor's Office, said investigators are aware of the video and others allegedly taken at the scene and are trying to track down witnesses through them.

"Killed him for no reason," the camera operator says as he moves toward the scene in the broad daylight of early afternoon on Aug. 9.

A group of residents stands several yards away from one side of the body, and three Ferguson Police Department SUVs are parked on the other side, with police officers walking toward them. Three minutes into the video, a man witnesses say is Brown's father approaches the prone body and then is quickly ushered away by two police officers.

The camera operator and another man are heard claiming that the police officer, who authorities later identified as Wilson, shot Brown as he held up his hands and said 'Don't shoot,' then stood over him and "shot him some more." But the camera operator acknowledges only hearing shots and not witnessing the shooting, and attributes the account to "that's what they said."

"They say he had his hands up and everything, and they just shot him anyway," the unidentified camera operator says.

With the police vehicles to the camera operator's left, and Brown's body facing them, a purported witness describes how Brown ran from the police.

"He was running away?" one man asks. "Why his body come this way, though?"

Dorian Johnson, a friend of Brown's who was with him when he was shot and is suspected to have been present moments earlier when Brown carried out a strong-arm theft of a box of cigars at a liquor store, has claimed Brown was never reaching over or into Wilson's squad SUV. He has claimed that Wilson struck Brown with the vehicle door as he got out, then fired at Brown as he ran away, continuing to shoot even after Brown turned to face him, his hands in the air in surrender.

An autopsy conducted at the request of Brown's family by Dr. Michael Baden, the noted former chief medical examiner of New York, reportedly determined that Brown was hit with six bullets, four to the right arm and two to the head, all to the front and none from close range. One of the bullets entered the top of Brown’s skull, suggesting his head was bent forward.

“This one here looks like his head was bent downward,” Baden told The New York Times. “It can be because he’s giving up, or because he’s charging forward at the officer.”

Police have said Wilson confronted Brown because he was walking in the middle of the street and have given differing information about whether Wilson was aware that Brown was a suspect in the robbery. Police said Brown struggled with the officer and reached for his weapon after being confronted, though several witnesses have claimed Brown raised his hands and was not attacking the officer.

Wilson is in seclusion and his account has not been made public. But a woman who claimed to be a close friend of his family told a St. Louis radio program that when Wilson tried to get out of his vehicle, Brown slammed the door shut on him. When Wilson finally managed to exit the SUV, Brown rushed him and punched him, according to the woman, whose association with Wilson's family was not verified by the radio program

U.S. Attorney General Eric Holder has approved a third autopsy on Brown's body, which will be conducted by a federal medical examiner.

The shooting touched off several days of protests that have ranged from peaceful to violent, and have included looting. Police have been blamed for exacerbating the protests with a military-style response that critics say inflamed demonstrators and turned the city of 21,000 into what some have likened to a "war zone."

The FBI has opened a civil rights investigation into the shooting, and President Obama has called for calm and issued a statement expressing condolences to the family and the community. Missouri Gov. Jay Nixon has declared a state of emergency and implemented a midnight-to-5-a.m. curfew in the city.