The Michael Brown killing: What you need to know

What facts are most pertinent?

The big question is whether Wilson legitimately believed, as police have said, that Brown posed a threat to his safety or his life. Some witnesses painted a different picture, saying Brown had his hands raised in surrender.

What do we know about the shooting?

Wilson, who was in a patrol vehicle, initially stopped Brown for jaywalking, because he and a friend were walking in the middle of Canfield Drive, a quiet street located off busy West Florissant Avenue. Brown was not armed.

Brown’s friend, Dorian Johnson, and police officials agree that Wilson got out of the car and that he and Brown had a physical struggle, although which of them started it is at issue.

Two autopsies, one of them commissioned by the Brown family, found that six bullets struck Brown, all of them from the front. He had wounds to one hand, an arm, his chest and head. The St. Louis County coroner’s report said the hand wound showed traces of material that could have come from the barrel of the gun, suggesting that the shot was fired at close range. A third autopsy was ordered by the U.S. Justice Department but has not been made public.

When the fatal shot struck Brown on the top of the head, he was roughly 35 feet from Wilson’s vehicle, indicating that at some point he had moved away from it.

What do we not know?

Police say that when Wilson got out of his SUV, Brown tried to shove him back into the vehicle and reached for the officer’s gun, prompting the first shots.

Johnson said that after telling the teens to get on the sidewalk, Wilson started to drive away, then reversed his vehicle and struck Brown with the SUV’s door. He said the officer then got out of the car, struggled with Brown and began to shoot.

Some witnesses said Brown was shot while fleeing from the officer, a scenario not supported by the autopsies. Some, including Johnson, said he ran but then turned and held his hands up in surrender.

Police said he turned back toward the car and charged the officer, who fired to protect himself.

Who was Michael Brown?

Brown, who was 18, had recently graduated from high school and was set to begin his freshman year at Vatterott College. He was shot to death at around noon on Aug. 9. in front of his grandmother’s house. Shortly before the shooting, Brown had gotten into a scuffle with a store clerk over a box of cigars.

Who is Darren Wilson?

Wilson is a 28-year-old white police officer, who has been with the Ferguson Police Department for six years. He had no prior disciplinary record. When he stopped Brown, he was unaware of the cigar incident.

What do we know about the grand jury?

The grand jury began hearing evidence in the case in late August. It includes six white men, three white women, two black women and one black man.

What happens after the grand jury’s decision?

Missouri Gov. Jay Nixon has already activated the National Guard and declared a state of emergency in case civil unrest breaks out.

If Wilson is indicted, a separate jury will hear the evidence at trial and decide his guilt or innocence.

The Ferguson police chief Thomas Jackson has already indicated that if Wilson is indicted, he will be fired. He hasn’t decided what would happen if Wilson gets off. He has been on paid administrative leave – and in hiding – since the shooting.