Let this be a lesson in always reading everything closely.

New convenience store footage of Michael Brown on the day he was shot and killed by a Ferguson police officer has emerged in a documentary which premiered Saturday at the South By Southwest festival in Austin. The footage shows Brown shortly after 1AM, eleven hours before his fatal encounter with Officer Darren Wilson, engaging in what appears to be an exchange with store clerks: Brown hands them a small bag which the clerks sniff and examine — per the filmmaker Jason Pollack’s voiceover, it is presumably weed — and the clerks hand him two boxes of cigarillos in return. Brown walks toward the door, then turns back to hand the box back to the clerks before leaving.

After the documentary’s premiere, county police have said they didn’t release the footage because they deemed it was irrelevant to the case. The only footage police chose to release was the infamous tape of Michael in the same convenience store later that afternoon, pushing a worker at the store and taking the cigarillos, minutes before Wilson shot him. Police claimed this video as evidence that Brown had robbed the store.

In his documentary Stranger Fruit, Pollack suggests this previously unreleased footage was in fact crucially relevant to the case, in that it undermined the police’s theory that Brown had robbed the store. Pollack argues this footage paints a picture of a more intimate relationship between the store employees and the slain teen, involving an early morning drug deal and a later-day misunderstanding just before Brown was killed.

We are now free to draw inferences from this footage of what occurred and how it relates to Brown’s death at the hands of a Ferguson police officer — and certainly, the Ferguson police and the convenience store’s representatives reject Pollack’s interpretation — but this begs the questions: Where has this footage been, how did it emerge, and why are we only seeing it now? Why was the public, the prospective jury pool, and the actual jury deprived the opportunity to have this more robust understanding of Brown’s interactions at the Ferguson Convenience Store, especially since the idea that Officer Wilson was apprehending a supposed robber was central to the idea that he was operating with a heightened state of fear for his own safety (which was claimed to justify his shooting)? (Note: This theory was successful, as the grand jury chose not to indict Officer Wilson.)

While the whereabouts of the footage all this time prior to Stranger Fruit is unclear, credit the documentary filmmaker Jason Pollack for bringing the tape to light. And his methods were available to anyone who bothered to take the time to read: Pollack pored over the St. Louis County police department’s records of their review of the case and discovered a brief mention of the video which the St. Louis county officials had viewed and described. And he found himself a bombshell.

“They destroyed Michael’s character with the tape, and they didn’t show us what actually happened,” Pollack has said. “So this shows their intention to make him look bad. And shows suppression of evidence.”

This footage doesn’t bring any more clarity to the fatal altercation between Brown and Wilson itself, but the revelation of its existence and the police department’s withholding it has rekindled outrage amongst those who feel Brown never saw justice from a police department which sought to paint him as a criminal.

Darren Wilson was not indicted and the revelation of this can not change that fact. But the incendiary outrage that engulfed Ferguson and ignited a worldwide #BlackLivesMatter movement has been stoked again by Stranger Fruit, while the Brown family has a new leg to stand on in their upcoming civil trial against the city of Ferguson and former officer Wilson. And those who are investigating, or documenting, or engaging in activism of any sort have been given a fresh lesson in the power of attention to detail and open eyes in the face of institutional opacity.

Here’s an interview with the store clerks:

REVOLT News | Previously unreleased surveillance video of Michael Brown surfaces