Documentary filmmaker Jason Pollock says the footage shows Brown leaving marijuana in what Pollock says was an exchange for cigarillos and two cold drinks.
When Brown took cigarillos from the store later that day, Pollock argues, he was collecting the goods he had bartered for, not committing robbery.
But the St. Louis County prosecutor and an attorney for the convenience store dispute Pollock's version of the events before Brown was shot and killed by Police Officer Darren Wilson.
CNN viewed the video released by the convenience store's attorney. In it, Brown can be seen placing an item on the counter. A clerk picks it up, smells the item and appears to place it back on the counter. Another clerk then picks it up and smells it, and appears to put it back on the counter. It is unclear what happens to the item after that point.
A third clerk then places Brown's store merchandise -- what appears to be cigarillos and soda -- in a grocery bag on the counter. Brown picks up the bag, and as he walks away, there appears to be a discussion. Brown returns to the counter, hands back the grocery bag and walks away.
One camera angle from behind the counter appears to show a clerk taking the box of cigarillos out of a grocery bag and putting it back on a shelf. That clerk then appears to hand the other items in the bag to another clerk who walks off camera with them.
The entire exchange lasts one minute and 55 seconds.
It is unclear what item Brown placed on the counter, and who possessed that item when he left the store.
Here's what Pollock says happened, and the response from the two lawyers:
On the length of video released:
Pollock's documentary contains 55 seconds of footage showing Brown inside the store. The convenience store's video includes another camera angle and shows him inside for about three and a half minutes.
Filmmaker Jason Pollock: "We show the entire exchange. We show the exchange from behind the counter. We chose to use that camera angle so that you could see the counter clearly during the entire exchange. At no time does the little bag come back across the counter. You can clearly see what happens."
Robert McCulloch, St. Louis County prosecutor: "Over the weekend there was a pretty pathetic attempt at a video production regarding the fatal shooting of Michael Brown in Ferguson that was released at a fair somewhere in Texas I believe. Contained in that was a very poorly edited snippet of a security video taken from the store in Ferguson about 12 hours before Michael Brown returned to the store and shortly before he was shot that has generated some questions and inquiries from both the public and media regarding the content, the source, the origin of that particular video."
Jay Kanzler, convenience store attorney: "If you are going to show the video, you don't show 20 seconds of the video you go and show it and then you sit down with all those people that were there and you say -- here's the whole video -- what happens here here here and here. And I've done that over and over again. The filmmaker didn't do that. Instead -- he came up with his theory and cut to his theory."
On what the video shows
Pollock: We have spoken to a lot of people in the community and trading a little bag, for something at the store is very, very common. There's a drug dealer -- we found out -- in the store. So what Michael did, he's not a drug dealer, OK, he traded a little bit for $20 of cigarillos. That happens all the time in communities where there's not a lot of money you barter with each other. What happened at the store is commonplace and you can see what it is because they smell it -- he takes it and they smell it."
McCulloch: Mr Brown put something on the counter. There's a discussion clearly going on there. Everything is in the bag. Mr. Brown and the clerks were examining whatever it was he put on counter. Mr. Brown had a discussion with them, picked up the bag and started to walk out of the store. One of the clerks said something to him, he returned, put the bag back on the counter, continued a discussion with them and then took something off of the counter itself and walked out of the store."
Kanzler: "They make it sound like he put the bag up there 'hold the bag for me, we'll go ahead and ...' No -- they unpacked it. They put the soda back. They put that back and he walks out with two things in his hand. The one is the piece of paper and the other is the pot."
On when the surveillance footage was released
Pollock: "We originally found the paperwork in the St. Louis County Police report, which shows that they saw at 1:13 a.m. a video of Michael Brown walking into the convenience store. That tipped us off that this happened. They admit that it happened in their own report, in the document that we found proves it ...
"What this video shows is that they [St. Louis County Police] lied to the world about what happened. They wanted to make Mike look bad so they put out half a video to destroy his character in his death."
In a separate CNN interview Pollock says: "We saw the altercation take place in the second half of the video -- the video that the St. Louis County Police wanted us to see that made it look like there was some altercation that looked like Michael robbed. When in fact Michael had a close relationship with the store and regardless of what the store says, the video shows that."
McCulloch: "That whole video was examined early on in this. We were well aware of it -- we issued the search warrant to obtain it. It was determined early on -- this was not new, everyone knew about it -- that it was neither relevant nor material to anything that occurred later that day around noon in the store or on Canfield Drive. As I'm sure you recall, I indicated that we were putting everything in front of the grand jury that would've been admissible at trial had there been an indictment out of it. This clearly would not have been admissible and so that was not presented then to the grand jury which means then that it wasn't released ...
"But I think it's important to note that the conversation that police had with the store employees is documented in the police report which was released on November 24, 2014. The application for a search warrant and the discussion around getting a search warrant for this information is also in the same police report and ultimately a description of the content of the video is in that police report. All of which was released on November 24, 2014 as part of the release that I made that night after the grand jury returned its verdict."
Kanzler: "I gave them this. The entire DVR. Three or four days after. They came with a search/not a search warrant subpoena and they came. And the Friday after Sunday that Michael Brown died the City of Ferguson released the one section of it. That was the first night Ferguson Market was looted.
"... It's not the prosecutor it's the City of Ferguson that released it. St. Louis County never released any of it ... and I don't know why ..."
On the video's significance
Pollock: "The video is a distraction. Everyone please understand this: The video is a distraction, the convenience store is a distraction and the reason we released it this way is because my film, 'Stranger Fruit' is about what really happened. Is about the physical evidence on Canfield. The evidence that they don't want us talking about. So we decided to get this video out of the way today. Let America and the world see that Mike didn't rob the store -- that that was all a lie -- and now we get to talk about the real physical evidence at Canfield... [which] proves that Darren Wilson murdered Michael and he should be in jail for that."
McCulloch: "This is not new information. It's certainly not a surprise to anyone. It's certainly not relevant or material to anything that occurred later in the day around noon at the store or shortly after that on Canfield Drive. It's not as though this was hidden away somewhere as this fellow with his video project was trying to say. If you look even at his pathetic video, it shows the police report where he got the information so it's all there and it's there since November of 2014. It's available. It's not edited."
Kanzler: "It's important to see this because you see the whole transaction you see there was no deal. He's [Pollock] saying there was a deal. There was no deal. There was no pot left behind. There was no understanding. They gave the pot back and there was this argument this 'get out of my store we don't want none of this.' "