A point of frustration among many of the people watching this unfold is how little information is out there — and how long it took for police to reveal any details at all. Police waited nearly a week to release Wilson's name, for instance. And although rumors abound, there is still so much we don't know about either the shooting or the investigation. Here are nine important details that are still unclear.
1) What Darren Wilson says happened during the shooting
Jon Belmar, the chief of the St. Louis County police department, which is investigating the shooting, gave the press what is presumably a summary of Wilson's version of events, saying that "the genesis of this was a physical confrontation," in which Wilson tried to get out of his car, and Brown pushed him back in. According to Belmar, Brown then assaulted Wilson and attempted to grab his service weapon, and a shot was fired from inside the police car. However, Belmar refused to give more details about what happened, citing a fear that he might "prejudice the case."
That means that we don't know anything about what Wilson says Brown was doing when he fired the fatal shots. Almost every known eyewitness has said that Brown ran away from Wilson, then, when Brown turned around with his hands up, Wilson continued to shoot until the teenager fell to the ground. As Dara Lind explains, these missing details are some of the most important when it comes to Wilson's legal case. We also don't know where Wilson is — he hasn't been arrested, his location is not publicly known, and he hasn't made any public statements or appearances since the shooting.
2) Whether Darren Wilson was injured
Ferguson police chief Tom Jackson said during a press conference that Wilson went to the hospital after the shooting and was treated for a "swollen face," but it's not at all clear what that means, because "swelling" is not a type of injury.
Initial reports that Wilson had a broken eye socket have been debunked, and there have not been any credible reports that Wilson suffered other injuries.
3) Why the St. Louis County Police Department waited so long to investigate the shooting
Immediately after the August 9 shooting, the Ferguson Police Chief transferred responsibility for the investigation to the St. Louis County Police Department. However, the county police department's investigation appears to have taken a long time to get underway. For instance, the police apparently did not interview Brown's friend Dorian Johnson, who was with Brown when he was killed, until Wednesday, August 13.
4) The results of the St. Louis County Police Department's investigation
We don't know any real details about the investigation — including how many witnesses police spoke to, or what those witnesses said. The results of the investigation have not yet been made public.
5) What evidence the county prosecutor is presenting to the grand jury
On Wednesday, August 20, the St. Louis County prosecutor's office began presenting evidence about the shooting to a grand jury. County Attorney Robert McCulloch has promised that "absolutely everything will be presented to the grand jury. Every scrap of paper that we have. Every photograph that was taken."
But that statement doesn't tell us very much, because we don't know what evidence McCulloch has, or how he's presenting it. This is a question that probably won't get answered. Grand jury proceedings are secret by default, and it's very rare for their records to be made public.
6) Why the Ferguson police released security footage of a convenience store robbery
On August 15, Chief Jackson released video footage that suggested Brown stole cigars from a local convenience store shortly before his death.
Jackson initially said that he was forced to release the video because of "sunshine requests" for the records, but the St. Louis Post-Dispatch, which reviewed all of the records requests that the police department had received before releasing the video, found that none of them called for information about the convenience store robbery.
Brown's family said, through their lawyer, that they believed the release of the robbery footage was "strategic" and an "attempt at character assassination." Many local residents greeted Jackson's announcement with outrage. There are also reports that Jackson released the robbery footage and police report over objections from the Department of Justice officials, who were concerned it would inflame tensions. It did.
7) How much Darren Wilson knew about the convenience store incident when he shot Brown
On August 15, a few hours after the convenience store footage was released, Jackson stated that Brown was stopped for jaywalking, not because of the robbery. But Jackson later told the St. Louis Post-Dispatch that, after the stop, Wilson realized Brown could be a suspect in the robbery when he noticed that Brown was carrying cigars.
Even if Wilson was aware of the robbery, we still don't know what he knew about it. That matters, because as Vox's Dara Lind explained here, the rules on whether police can use deadly force depend in part on whether the target is a suspect fleeing a "violent felony." It does not seem particularly plausible that Wilson could have believed Brown was fleeing a violent crime — after all, the stated reason for the initial stop is that Brown was ambling slowly down the middle of the street with a friend — but it's hard to know for sure without details.
8) How many shots Wilson fired
Michael Brown was shot at least six times, according to a preliminary report on an independent autopsy commissioned by Brown's family. Dr. Michael Baden, who conducted the autopsy, found that two of the shots hit Brown in the head, and that all appeared to have been fired when Brown was facing Wilson.
We don't know if those six shots were the only ones that Wilson fired, or if there were additional shots that missed. We also don't know how far away Brown was from Wilson when he was shot.
9) What the official state or federal autopsy reports say
In addition to the private autopsy conducted at the behest of Brown's family, two official autopsies were conducted as well: one by the St. Louis County Medical Examiner, as part of the state investigation into the shooting, and one by a federal medical examiner, as part of the federal investigation.
Mary Case, the county medical examiner, said that Brown was shot in the head and chest multiple times, but has not made the results of the county autopsy public. On August 18, someone with knowledge of the county autopsy told the Washington Post that the toxicology report showed that Michael Brown had marijuana in his system at the time he was killed. (That information has essentially no bearing on what happened during the shooting or who was at fault.)
We don't have any information about the results of the federal autopsy yet, but Justice Department spokesperson Brian Fallon said that DOJ officials "still plan to take the state-performed autopsy into account" in their investigation.