Read the DOJ report, Wilson was chasing down Brown because after Brown tried to take Wilson's gun, and the gun discharged into Browns hands, Wilson felt Brown was a threat. Brown turned around and then charged Wilson, the evidence of the shell casing being behind Brown prove he was charging.
It's all in the DOJ report. It also found that many witnesses accounts were not credible.
So the shell casings were behind the direction Brown was running from ? didnt quite see that. but this clip is also from th ereport.
9. Brown’s Toxicology A toxicologist with the St. Louis University (SLU) Toxicology Laboratory and the Chief of the Division of Forensic Toxicology at AFMES each conducted blood and urine screens on samples collected from Brown’s body. Brown tested positive for the presence of cannabinoids, the hallucinogenic substances associated with marijuana use. The SLU Toxicology Laboratory found 12 nanograms per milliliter of Delta-9-THC, the active ingredient in marijuana, where AFMES found 11 nanograms per milliliter of Delta-9-THC in Brown’s blood. According to both laboratories, these levels of Delta-9-THC are consistent with Brown having ingested THC within a few hours before his death. This concentration of THC would have rendered Brown impaired at the time of his death. As a general matter, this level of impairment can alter one’s perception of time and space, but the extent to which this was true in Brown’s case cannot be determined. THC affects individuals differently depending on unknown variables such as whether Brown was a chronic user and the concentration of the THC ingested.