Q&A; So what was Michael Brown doing when he was shot?
MICHAEL Brown and his 22-year old friend Dorian Johnson left a convenience store at 11.54am. A surveillance video showed Brown stealing some cigarillos.
What did Officer Wilson do?
Just after midday, speaking through his vehicle window, Officer Wilson told the two men to move to the pavement.
Mr Johnson, who was a witness interviewed by the grand jury, told MSNBC the officer told the pair to "get the fuck onto the sidewalk".
The officer then saw that Brown fitted the description of a suspect in a convenience store theft. An altercation occurred between the police officer and Brown, who was standing at the window.
What evidence was presented to the grand jury?
Johnson said that Wilson attempted to push his door open, but the door slammed into Brown and bounced closed.
Johnson said the officer, with his left hand, grabbed Brown by the neck. Several witnesses reported seeing an altercation between Wilson, who was in his SUV, and Brown.
Other witnesses said that Brown punched Wilson while he was leaning inside the vehicle. A medical examination indicated that Officer Wilson had some swelling and redness on his face.
What does the grand jury do?
It doesn't determine guilt or innocence. Its role is to decide whether there is enough evidence to put a suspect on trial.
It generally consists of 16 to 23 members chosen at random, although there were only 12 on Wilson's case.
The grand jury meets in secret with no judge or lawyer present and only works with the prosecutor who explains to them the law and presents the evidence.
What happened next?
Wilson fired two shots from inside the vehicle. The first one grazed Brown's right thumb but the other missed him.
Examiners found Brown's blood outside the driver's door. inside the driver's door, on the upper left thigh of Officer Wilson's trousers and on the officer's shirt and weapon.
As the young men started running, the officer decided to pursue on foot. Brown stopped and turned toward the officer, who fired several more shots, fatally wounding the teenager.
Was Brown attacking him?
There is a mass of conflicting testimony from 60 witnesses. Some told the jury Brown never moved toward Wilson when he was shot and killed. Most witnesses said shots were fired as he moved toward the officer.
What killed Michael Brown?
Brown sustained at least six more wounds from the 10 rounds fired by the officer in the street. The wounds on his forehead and the top of his head suggested that Brown's body was bent forward at the waist.