"Prosecuting Attorney Robert P. McCulloch described the process that he used. The grand jury was one that a judge had previously selected, well before the shooting occurred. After the shooting, the grand jurors were asked to extend their service to hear the evidence. Prosecutors then called before the grand jury everyone they could that had evidence relevant to the case. The St. Louis Post-Dispatch summarized the process neatly:" ...
Darren Wilson explains why he killed Michael Brown ... "On a hot August day, Wilson drove down a street and spotted two young black men walking down the middle of the road. One wore a black shirt. The other held cigarillos. The details of a robbery earlier that day, blared out on a police radio, clicked into Wilson’s head. Were they suspects? He told the two young men, one of whom was Brown, to move to the sidewalk.
"Things then happened very quickly. Wilson said Brown was at his car window, enraged. Wilson said Brown hit him in the face, grabbing for his gun. Two shots fired. Brown bolted down the street. Wilson pursued. As Wilson told it, Brown charged the officer, reaching into his pants. Wilson raised his .40-caliber Sig Sauer and aimed for a lethal shot."
Ferguson officer: 'I know I did my job right' ... "Wilson says he felt like it was his duty to chase Brown after a confrontation at his police vehicle. When asked about witness accounts that Brown at one point turned toward Wilson and put his hands up, he responded "that would be incorrect.' "