Let's look at Darren Wilson's account of that final encounter. On the day of the shooting, Wilson gave a statement about what happened; the statement can be found in this document. Wilson later gave a statement to the grand jury. Certain details differed between the two statements, but the broad strokes of what he described were the same. Because the initial statement was given when the event was fresh in Wilson's memory, it should be more reliable.

According to Wilson, after Brown began to "charge" toward him in the street,

P.O. Darren Wilson continued to give Brown commands to stop; however, Brown ignored them. Once Brown got within approximately 15 feet of him, P.O. Darren Wilson indicated he discharged five rounds to stop the threat. According to P.O. Darren Wilson, this did not slow Brown down and he continued to advance. P.O. Darren Wilson discharged two additional rounds; however, Brown continued to advance. P.O. Darren Wilson stated Brown then leaned forward and appeared as if he (Brown) was attempting to "tackle" him. P.O. Darren Wilson then discharged one additional round to stop the threat. Brown then fell to the ground, ending the threat.

To summarize: Wilson claims that Brown was charging toward him, that Wilson began to fire his gun when Brown was about 15 feet away, and that Brown continued to advance without slowing down until the final gunshot stopped him.

Is there an objective timeline of these gunshots? Fortunately for us (and unfortunately for Wilson, had the prosecution actually been interested in prosecuting the case), there is. A nearby resident who was in an online voice chat at the time obtained audio of all the gunshots fired in the street (that is, the two gunshots that occurred at Wilson's SUV were not included). Here is a visualization of the recording:



We can see that six shots (marked in red) were fired within a span of approximately two seconds. There was then a three second pause before the seventh shot was fired. The eighth shot came one second later, followed quickly by shot 9 and then shot 10. The total time was 6.572 seconds.

To reiterate, Wilson claims that Brown was charging toward Wilson throughout the time that Wilson fired these shots. It seems a fair assumption that Wilson's use of the word "charge" would mean that Brown was sprinting. How much ground can a sprinting human cover in 6.572 seconds?

Let's start, just for curiosity's sake, with the fastest speed ever recorded for a human on foot: 27.44 mph by Usain Bolt. At that speed, Bolt would cover 264 feet in 6.572 seconds.

Obviously, Brown wasn't an elite sprinter; he doesn't look to have been much of an athlete, period. So let's try to get a more realistic estimate. Your average human isn't going to have a record of their sprinting speed available. One place where humans are regularly recorded sprinting short distances is the NFL combine's 40 yard dash. In 2014, the fastest 40 yard dash time was running back Dri Archer's 4.26 seconds; the slowest was offensive lineman Cyrus Kouandjio's 5.59 seconds. Kouandjio's listed measurements are 6'6", 311 pounds, so he's of similar proportions to Michael Brown's 6'4", 292. Still, Kouandjio is an athlete, unlike Brown.

Every year at the combine ESPN's Rich Eisen also runs the 40 just for fun, wearing a full suit. This year he ran it in 5.98 seconds.

The average speeds: a really fast NFL player, 19.2 mph. A really slow NFL player, 14.6 mph. A 45-year-old non-athlete, 13.7 mph. Because these dashes came from stationary starts, these are lower than the top sustained speeds, but I'm more interested in a low-end estimate, so that's okay. Additionally, the National Council on Strength & Fitness says that "the average man can run about 15 mph for short periods."

Let's be really conservative and say that Michael Brown could only sprint at 10 mph. (For another point of reference to how slow of a "sprint" this would be, world-class marathoners can maintain 12 mph for two hours.) Even at 10 mph, he could have covered 96 feet in 6.572 seconds.

To summarize: Darren Wilson claims that he started shooting at Michael Brown when Brown was 15 feet away and charging toward him, and that Brown continued to advance without slowing until the final shot was fired. A conservative estimate of the distance Brown would have covered if he was continuously charging for the duration of the shots is more than 90 feet.

The bottom line: Wilson's description of the events is simply impossible given the physical evidence.

Now, one possible objection is, what if Wilson was backing up? A couple of problems with that: if Brown was really "charging" and already just 15 feet away when the shots started... imagine someone running backwards for six seconds at nearly the same speed as someone charging toward him, all while aiming and firing a gun... pretty preposterous, no? Secondly, according to the audio analysis expert quoted in the Washington Post article I linked:

Clark [Ralph Clark, CEO of ShotSpotter] said the recording has a three-second pause after the first six shots before the final four shots. His experts were also able to confirm that the shots were all taken from within a three-foot radius – there was only one shooter and that person was not moving.

Humans, of course, have far from perfect memories. If someone recalled a distance as being about 15 feet when it was actually more like 20 feet, or was a little off on the number of shots fired, I wouldn't consider that a serious issue. But this, this is far more than a minor discrepancy. Wilson's account of what happened is different on a fundamental level from what actually happened.

This is a huge problem. There's no disputing the fact that Wilson shot and killed Brown. The grand jury's decision not to indict essentially means that they believed Wilson's explanation for why the shooting was justified. If that explanation was clearly not accurate, there has to be a trial to try to determine what really happened and whether Wilson committed a crime.

What did really happen? This part is more speculative, but I think that this summary of the various witness statements, in conjunction with the physical evidence, is useful. It's clear that no witnesses agree on 100% of the details. This is not an unusual problem about this particular case. It's just the nature of human memory. However, if sizable majorities of witnesses agree about the answers to certain questions, it makes it more likely that those answers are grounded in reality. In this case, large majorities answered yes to the questions of whether Wilson fired at Brown while Brown was running away, and whether Brown had his hands up when he was fired upon.

Let's put this in the context of the objective audio record that shows an initial salvo of gunfire, a three second pause, and then a second salvo.

I'd posit that the scenario best fitting the evidence is this: Brown was running away with Wilson in pursuit. As Wilson (almost certainly a faster runner) gained on Brown, Wilson fired the first six shots toward Brown's back. Brown, realizing that Wilson was attempting to kill him, stopped fleeing and turned around. He raised his hands in surrender and began to walk slowly toward Wilson. (It's important to note that the blood trail did show Brown moved a total of 25 feet back in the direction of Wilson before his body came to rest in the street.)

I'm willing to give Wilson the benefit of the doubt and say that he probably didn't intentionally execute an unarmed, surrendering suspect, but instead was panicking. He fired again, hitting Brown. Now badly wounded, Brown began to stagger forward, lowering his arms and head. At this point, Wilson fired the final shots that killed Brown.

Do I know for sure that this is what happened? No, I don't, but I do know for sure that what Wilson said happened is not what happened. Note that in saying that, I'm not relying on any sort of wild conjecture or conspiracy theorizing. I'm simply comparing Wilson's statement to an objective record of the events, and showing that the former directly and dramatically disagrees with the latter.

Did Wilson lie? Here, I can't be certain. It's quite possible that he did lie, because he knew that firing at a fleeing suspect was a crime, and he didn't know that the events would be recorded to show his statement was false. But it's also possible that, after a highly traumatic event, his subconscious mind, not able to process the fact that he'd just committed murder, reconstructed the events in a way that justified his actions and that he came to honestly believe.

Either way, Wilson's account is clearly false, and the decision to not put him on trial is a travesty.