Story highlights Brown rushed full speed at officer, an account called in to St. Louis radio station claims

A source with detailed knowledge of the investigation says the account is accurate

Autopsy suggests Brown kneeling or bending forward when shot in head, lawyer says

Another tense standoff developed Monday night in Ferguson, Missouri, which has seen nightly protests since unarmed 18-year-old Michael Brown was shot to death by a white police officer.

The renewed tensions came after the preliminary results of an autopsy that Brown's family requested were released, as was a new account of what allegedly happened in the moments immediately before the teenager was killed by a local police officer.

Evidence in the shooting death could be presented to a grand jury as early as Wednesday.

And as the situation in the St. Louis suburb was being watched and talked about across the country, it continued to draw comments from numerous quarters -- including the White House.

"We have all seen images of protesters and law enforcement in the streets. It's clear that the vast majority of people are peacefully protesting. What's also clear is that a small minority of individuals are not," said President Barack Obama.

A diagram from the autopsy shows entry and exit wounds.

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"While I understand the passions and the anger that arise over the death of Michael Brown, giving into that anger by looting, or carrying guns, and even attacking the police only serves to raise tensions and stir chaos," he said, in a call for calm.

"Let's see some understanding" rather than confrontation, and "let's seek to heal," the President said.

Officials temporarily detained several people, including news photographer Scott Olson and longtime activist and Holocaust survivor Hedy Epstein.

Dueling narratives

The officer who killed Brown says the teenager rushed at him full speed in the moments before the shooting, according to an account phoned in to a St. Louis radio station and confirmed by a source with detailed knowledge of the investigation.

According to the version on KFTK , phoned in by a woman who identified herself as "Josie," the altercation on August 9 began after Officer Darren Wilson rolled down his window to tell Brown and a friend to stop walking in the street.

When Wilson tried to get out of his cruiser, Brown first tried to push the officer back into the car, then punched him in the face and grabbed for his gun before breaking free after the gun went off once, the caller said.

Wilson pursued Brown and his friend, ordering them to freeze, according to the account. When they turned around, Brown began taunting Wilson, saying he would not arrest them, then ran at the officer at full speed, the caller said.

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Photos: Photos: Emotions run high in Ferguson Photos: Photos: Emotions run high in Ferguson Protesters march in Ferguson, Missouri, on Thursday, August 21 2014. The St. Louis suburb saw turmoil after a white police officer, Darren Wilson, fatally shot an unarmed black teenager, Michael Brown, on August 9, 2014. Some protesters and law enforcement officers clashed in the streets, leading to injuries and arrests. Hide Caption 1 of 76 Photos: Photos: Emotions run high in Ferguson A crowd gathers in Ferguson on August 21, 2014. With the situation appearing to calm, Gov. Jay Nixon ordered the Missouri National Guard to begin withdrawing from the city. Hide Caption 2 of 76 Photos: Photos: Emotions run high in Ferguson Police escort a Wilson supporter to a police vehicle, away from crowds protesting Brown's death on Wednesday, August 20, 2014. Police have said Brown and Wilson struggled over the officer's gun; some witnesses said Brown had his hands in the air when he was shot. Hide Caption 3 of 76 Photos: Photos: Emotions run high in Ferguson Lightning streaks over protesters on August 20, 2014. Hide Caption 4 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators protest on August 20, 2014. Hide Caption 5 of 76 Photos: Photos: Emotions run high in Ferguson U.S. Attorney General Eric Holder meets with Capt. Ron Johnson of the Missouri State Highway Patrol at a Ferguson restaurant on August 20, 2014. Holder came to Missouri to talk to community leaders and review the federal civil rights investigation into Brown's shooting. Hide Caption 6 of 76 Photos: Photos: Emotions run high in Ferguson Protesters march through the streets of Ferguson on August 20, 2014. Hide Caption 7 of 76 Photos: Photos: Emotions run high in Ferguson Police point out a demonstrator who has his arms raised before moving in to arrest him Tuesday, August 19, 2014. Hide Caption 8 of 76 Photos: Photos: Emotions run high in Ferguson People watch from inside a restaurant as protesters rally August 19, 2014. Hide Caption 9 of 76 Photos: Photos: Emotions run high in Ferguson Police arrest a demonstrator on August 19, 2014. Hide Caption 10 of 76 Photos: Photos: Emotions run high in Ferguson Police charge into the media work area with weapons drawn as they try to control demonstrators on August 19, 2014. Hide Caption 11 of 76 Photos: Photos: Emotions run high in Ferguson A protester speaks to a police officer on August 19, 2014. Hide Caption 12 of 76 Photos: Photos: Emotions run high in Ferguson People on August 19 stand near a memorial where Brown was shot and killed, 2014. Hide Caption 13 of 76 Photos: Photos: Emotions run high in Ferguson Protesters march on August 19, 2014. Hide Caption 14 of 76 Photos: Photos: Emotions run high in Ferguson Police watch as protesters march August 19, 2014. Hide Caption 15 of 76 Photos: Photos: Emotions run high in Ferguson A demonstrator is arrested on August 19, 2014. Hide Caption 16 of 76 Photos: Photos: Emotions run high in Ferguson Police try to control protesters on Monday, August 18, 2014. Hide Caption 17 of 76 Photos: Photos: Emotions run high in Ferguson Police lead a man away during a protest August 18, 2014. Hide Caption 18 of 76 Photos: Photos: Emotions run high in Ferguson A demonstrator shouts during a protest on West Florissant Avenue, one of Ferguson's main streets, on August 18, 2014. Hide Caption 19 of 76 Photos: Photos: Emotions run high in Ferguson Capt. Ron Johnson of the Missouri State Highway Patrol pulls his men back from aggressive protesters on August 18, 2014. Hide Caption 20 of 76 Photos: Photos: Emotions run high in Ferguson Police arrest a demonstrator August 18, 2014, after peaceful protests gave way to angry confrontations with authorities. Hide Caption 21 of 76 Photos: Photos: Emotions run high in Ferguson Law enforcement officers stand guard during a protest on West Florissant Avenue on August 18, 2014. Hide Caption 22 of 76 Photos: Photos: Emotions run high in Ferguson A woman helps a man affected by tear gas August 18, 2014. The situation overnight deteriorated after a handful of protesters threw rocks, bottles and Molotov cocktails at police. Officers responded by firing stun grenades and tear gas canisters. Hide Caption 23 of 76 Photos: Photos: Emotions run high in Ferguson Officers stand with weapons drawn during a protest on West Florissant Avenue on August 18, 2014. Hide Caption 24 of 76 Photos: Photos: Emotions run high in Ferguson Musician Nelly, center, joins demonstrators in Ferguson on August 18, 2014. Hide Caption 25 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators receive red roses as they protest August 18, 2014. Hide Caption 26 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators march on August 18, 2014. Hide Caption 27 of 76 Photos: Photos: Emotions run high in Ferguson The Rev. Jesse Jackson shakes hands with a police officer as he visits Ferguson's demonstration area on August 18, 2014. Hide Caption 28 of 76 Photos: Photos: Emotions run high in Ferguson A protester picks up a tear gas canister on Sunday, August 17, 2014. Hide Caption 29 of 76 Photos: Photos: Emotions run high in Ferguson Police wait to advance after using tear gas to disperse protesters August 17, 2014. Hide Caption 30 of 76 Photos: Photos: Emotions run high in Ferguson Water gets poured into a woman's eyes after a tear gas attack by police on August 17, 2014. Hide Caption 31 of 76 Photos: Photos: Emotions run high in Ferguson A man runs through clouds of tear gas on August 17, 2014. Hide Caption 32 of 76 Photos: Photos: Emotions run high in Ferguson Protesters react as police fire tear gas at them August 17, 2014. Hide Caption 33 of 76 Photos: Photos: Emotions run high in Ferguson Police advance through a cloud of tear gas on August 17, 2014. Most of the crowd had dispersed after a curfew went into effect at midnight, St. Louis County authorities said. Hide Caption 34 of 76 Photos: Photos: Emotions run high in Ferguson People take cover from tear gas inside a McDonald's on August 17, 2014. Hide Caption 35 of 76 Photos: Photos: Emotions run high in Ferguson A large group of police officers advance toward protesters on August 17, 2014. Hide Caption 36 of 76 Photos: Photos: Emotions run high in Ferguson A man fights the effects of tear gas in Ferguson on August 17, 2014. Hide Caption 37 of 76 Photos: Photos: Emotions run high in Ferguson Michael Brown Sr. and Lesley McSpadden, the parents of Michael Brown, attend a rally at Greater Grace Church in Ferguson on August 17, 2014. Hide Caption 38 of 76 Photos: Photos: Emotions run high in Ferguson The Rev. Al Sharpton hugs McSpadden during the rally. Hide Caption 39 of 76 Photos: Photos: Emotions run high in Ferguson Capt. Ron Johnson of the Missouri State Highway Patrol speaks at the rally. He had been appointed by the governor to take control of security operations. Hide Caption 40 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators defy a curfew early on August 17, 2014. Hide Caption 41 of 76 Photos: Photos: Emotions run high in Ferguson Police fire tear gas at demonstrators after curfew on August 17, 2014. Hide Caption 42 of 76 Photos: Photos: Emotions run high in Ferguson A law enforcement officer aims his rifle August 17,, 2014, after tear gas was fired to disperse a crowd. Hide Caption 43 of 76 Photos: Photos: Emotions run high in Ferguson Law enforcement officers check a building on August 17, 2014. Hide Caption 44 of 76 Photos: Photos: Emotions run high in Ferguson People attend a protest after the midnight curfew on August 17, 2014. Hide Caption 45 of 76 Photos: Photos: Emotions run high in Ferguson A law enforcement officer watches as tear gas is fired to disperse a crowd on August 17, 2014. Hide Caption 46 of 76 Photos: Photos: Emotions run high in Ferguson Police stand guard before the midnight curfew on Saturday, August 16, 2014. Hide Caption 47 of 76 Photos: Photos: Emotions run high in Ferguson People loot the Ferguson Market and Liquor store on August 16, 2014. Several businesses were looted as police held their positions nearby. Hide Caption 48 of 76 Photos: Photos: Emotions run high in Ferguson Missouri State Highway Patrol officers listen to taunts from demonstrators during a protest on Friday, August 15, 2014. Hide Caption 49 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators protest with their hands up on August 15, 2014. The "hands up" gesture has become a symbol in protests as Brown, according to eyewitnesses, was trying to surrender when he was shot multiple times. Hide Caption 50 of 76 Photos: Photos: Emotions run high in Ferguson Police confront demonstrators on August 15, 2014. Hide Caption 51 of 76 Photos: Photos: Emotions run high in Ferguson A demonstrator throws a tear gas canister back at police on August 15, 2014. Hide Caption 52 of 76 Photos: Photos: Emotions run high in Ferguson Police confront demonstrators on August 15, 2014. Hide Caption 53 of 76 Photos: Photos: Emotions run high in Ferguson ri – Thousands of demonstrators march down a Ferguson street with members of the St. Louis County Police and the Missouri State Highway Patrol on Thursday, August 14, 2014. Hide Caption 54 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators hold signs as traffic moves slowly past them on August 14, 2014. Hide Caption 55 of 76 Photos: Photos: Emotions run high in Ferguson People scramble as police fire tear gas on August 17, 2014. Hide Caption 56 of 76 Photos: Photos: Emotions run high in Ferguson State Highway Patrol Capt. Ron Johnson smiles at demonstrators on August 14, 2014. Johnson was appointed to lead security as state troopers took over after days of clashes between protesters and local police. Hide Caption 57 of 76 Photos: Photos: Emotions run high in Ferguson The Rev. Traci Blackmon uses a megaphone to talk to a large group of demonstrators on August 14, 2014. Hide Caption 58 of 76 Photos: Photos: Emotions run high in Ferguson A man picks up a flaming bottle and prepares to throw it as a line of police advance in the distance on Wednesday, August 13, 2014. Hide Caption 59 of 76 Photos: Photos: Emotions run high in Ferguson Police stand in clouds of smoke as they clash with protesters on August 13, 2014. Hide Caption 60 of 76 Photos: Photos: Emotions run high in Ferguson An Al-Jazeera television crew runs for cover as police fire tear gas at its position on August 13, 2014. Video and images on social media showed police later breaking down the journalists' gear. Hide Caption 61 of 76 Photos: Photos: Emotions run high in Ferguson A protester runs from tear gas exploding around him on August 13, 2014. Hide Caption 62 of 76 Photos: Photos: Emotions run high in Ferguson Police stand guard among demonstrators on August 13, 2014 Hide Caption 63 of 76 Photos: Photos: Emotions run high in Ferguson Ferguson Police Chief Thomas Jackson fields questions during a news conference on August 13, 2014. Hide Caption 64 of 76 Photos: Photos: Emotions run high in Ferguson A small group of protesters block traffic in the street before police arrived on August 13, 2014. Hide Caption 65 of 76 Photos: Photos: Emotions run high in Ferguson A protester throws a tear gas canister back toward police on August 13, 2014. Hide Caption 66 of 76 Photos: Photos: Emotions run high in Ferguson Police detain a man on Tuesday, August 12, 2014. Hide Caption 67 of 76 Photos: Photos: Emotions run high in Ferguson People congregate at the Greater St. Marks Family Church in St. Louis along with the family of Michael Brown and the Rev. Al Sharpton on August 12, 2014. Hide Caption 68 of 76 Photos: Photos: Emotions run high in Ferguson Michael Brown Sr. stands alongside Sharpton, right, during a news conference in St. Louis on August 12, 2014. Hide Caption 69 of 76 Photos: Photos: Emotions run high in Ferguson Demonstrators protest August 12 in Ferguson, 2014. Hide Caption 70 of 76 Photos: Photos: Emotions run high in Ferguson A makeshift memorial sits in the middle of the street where Michael Brown was shot and killed. Hide Caption 71 of 76 Photos: Photos: Emotions run high in Ferguson A woman tries to calm an emotional protester during a demonstration outside the headquarters of the Ferguson Police Department on August 11, 2014. Hide Caption 72 of 76 Photos: Photos: Emotions run high in Ferguson Phaedra Parks, left, comforts Desuirea Harris, the grandmother of Michael Brown, during a news conference in Jennings, Missouri, on August 11, 2014. Hide Caption 73 of 76 Photos: Photos: Emotions run high in Ferguson Police officers arrest a man who refused to leave when police cleared streets in Ferguson on August 11, 2014. Hide Caption 74 of 76 Photos: Photos: Emotions run high in Ferguson A burned-out QuikTrip gas station smolders on August 11, 2014 after protesters looted and burned the Ferguson building the night before. Hide Caption 75 of 76 Photos: Photos: Emotions run high in Ferguson Police officers and protesters confront each other on Saturday, August 9, the same day Michael Brown was shot and killed. Hide Caption 76 of 76

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Wilson then began shooting. The final shot was to Brown's forehead, and the teenager fell two or three feet in front of Wilson, said the caller, who identified herself as the officer's friend.

A source with detailed knowledge of the investigation later told CNN the caller's account is "accurate," in that it matches what Wilson has told investigators.

But accounts of exactly what happened when Wilson stopped Brown vary widely.

Witnesses said they saw a scuffle between the officer and Brown at the police car before the young man was shot. Several witnesses said Brown raised his hands and was not attacking the officer.

Piaget Crenshaw said she was sitting in her home when she witnessed the shooting. She captured video of the aftermath, including images of Brown's body lying in the middle of the street.

Crenshaw said Brown was running away from police and then turned around. She said that was when Brown was shot.

Police provided a different narrative, saying Brown struggled with the officer and reached for his weapon.

Parallel investigations

A grand jury will hear testimony from witnesses and decide on whether to return an indictment in the case, Ed McGee, spokesman for the St. Louis County prosecuting attorney, said Monday, stressing there is "no time line on this case."

In addition to that proceeding, the Justice Department has opened a civil rights investigation into Brown's death. Attorney General Eric Holder will travel to Ferguson this week, to meet with investigators there.

"I realize there is tremendous interest in the facts of the incident that led to Michael Brown's death, but I ask for the public's patience as we conduct this investigation," the attorney general said in a statement.

"The selective release of sensitive information that we have seen in this case so far is troubling to me. No matter how others pursue their own separate inquiries, the Justice Department is resolved to preserve the integrity of its investigation."

Autopsy findings

An autopsy conducted for the family of Brown found no evidence that he struggled with Wilson before his death, according to the pathologist in charge of the examination.

Dr. Michael Baden conducted the autopsy after an official examination by the St. Louis County medical examiner's office.

Forensics consultant Shawn Parcells, who assisted Baden, said the findings are consistent with witness reports that Brown may have been shot as he walked away and that he was shot again with his hands up.

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The family autopsy found that Brown was shot at least six times, including two shots to his head. Three of the bullets may have re-entered his body, causing additional damage, Baden said.

One of the bullets entered his head and came out through his eye; another -- likely the fatal wound, Baden said -- struck Brown on the top of his head and caused irreparable damage to his brain.

Family attorney Benjamin Crump said Brown probably would have been either kneeling or bending forward when he was struck with those bullets.

Brown had abrasions on his face consistent with falling onto the ground, Baden said.

He cautioned that he needs access to autopsy results, including tests on Brown's clothes and X-rays, before making some conclusions.

But Crump said the autopsy already offered more than "ample" evidence to support Wilson's arrest.

"What does this autopsy say? That the witness accounts were true, that he was shot multiple times," Crump told reporters.

Attorney General Holder said a third autopsy was being conducted Monday by medical examiners from the U.S. military.

Devolution of protests

Another family attorney, Anthony Gray, implored protesters to remain peaceful.

"I can see that there is a very disturbing divide that is developing in our community," he said Monday. "This is not what we initially came to the community and called for."

The situation remains so unstable that the Ferguson-Florissant School District has canceled classes for the rest of the week.

The Missouri National Guard was in Ferguson under orders from the governor to restore peace.

Nixon issued the order early Monday after what began as peaceful protests spiraled into disarray after two civilians were shot and injured, Missouri State Highway Patrol Capt. Ron Johnson said. He said those civilians were not shot by police.

Some protesters hurled Molotov cocktails at police, and several businesses were vandalized or looted despite the Brown family's call for calm.

"Based on these conditions, I had no alternative but to elevate the level of our response," Johnson said.

Officers fired tear gas into hundreds of protesters, including children, who were marching toward a police command post despite an impending midnight curfew.

Two children were treated and released for exposure to tear gas overnight at St. Louis Children's Hospital, according to a spokeswoman there.

Protester Lisha Williams challenged the notion that protesters provoked officers.

"That is a lie. It was no fight, it was no shots fired," she told CNN late Sunday. "All we did was march to the command center to fall to our knees and say, 'Don't shoot.' And they started shooting."