FERGUSON, Mo. (CNN) - The Ferguson police officer who killed Michael 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 as accurate by a source with detailed knowledge of the investigation.
According to the account on KTFK radio, phoned in by a woman who identified herself as "Josie," (listen to the radio call below)the altercation 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. 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.
If true, the account represents the first telling of events from the perspective of Wilson, whose shooting of Brown has touched off nightly protests and violence in the suburban St. Louis city.
The news came the same day a spokesman for the St. Louis County prosecuting attorney said that evidence in the shooting death could be presented to a grand jury as early as Wednesday.
In addition to that case, 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, President Barack Obama said Monday.
The President called for calm, saying that violence undermines, rather than advances justice.
"Let's see some understanding" rather than confrontation, and "let's seek to heal," Obama said.
Earlier Monday, 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 said no signs of a struggle were revealed in his autopsy of Brown's body, conducted after an official examination by the St. Louis County medical examiner's office.
And 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.
Brown family attorney Daryl Parks said he was particularly concerned about gunshots that medical examiners hired by the family indicate came from behind and above.
"Why would he be shot in the very top of his head, a 6-foot-4 man?" Parks asked. "Makes no sense."