Story highlights A man recorded sounds of gunfire during a video chat with a friend, company says

Man's lawyer: He inadvertently recorded sounds of Michael Brown shooting

FBI obtained the video, lawyer says

The sounds could be a piece in the larger puzzle of what happened during the shooting

A company whose video chat service apparently captured audio of Michael Brown's shooting said Thursday the recording was created at the time the Missouri teenager was killed this month.

The revelation from Glide appears to bolster a man's claim that he inadvertently recorded audio of gunfire at the time a police officer shot and killed the 18-year-old Brown in the St. Louis suburb of Ferguson on August 9.

The video was created at 12:02:14 p.m. that day, Glide said. Brown, who was unarmed, was shot by Ferguson police officer Darren Wilson shortly after noon.

"A Glide user living nearby was simply using the Glide app on their smartphone exactly as it was designed -- to instantly communicate with a friend through our real-time video texting service. Simultaneously, they also captured audio in the background of the gunshots allegedly fired at Michael Brown," the company said.

The sounds could be a piece in the larger puzzle of what happened during the shooting, which spurred days of protests in the city of 21,000.

Police have said Brown was trying to grab the officer's gun. Witnesses say the teen was holding his hands in the air when he was fatally shot. Investigators are determining whether to accuse the officer of wrongdoing; no charges have been filed.

The FBI obtained the audio and interviewed the man who made the recording, said Lopa Blumenthal, a lawyer for that individual.

The man, who asked that his identity not be revealed, lives near the site of the Brown shooting and happened to be using the application at the same time Brown was shot, Blumenthal said.

In the recording, a quick series of shots can be heard, followed by a pause and then another quick succession of shots.

Forensic audio expert Paul Ginsberg analyzed the recording and said he detected at least 10 gunshots -- a cluster of six, followed by four.

The significance of the pause

Witnesses and a friend of Wilson have given conflicting accounts of what led to Brown's death , and the pause could be key in the investigation. But it's difficult to prove from the audio why the pause took place or whose narrative it supports.

Ferguson police have alleged that Brown robbed a convenience store shortly before the shooting, and that he and a friend, Dorian Johnson, were walking down a street when Wilson approached them in a police car.

Police say Wilson stopped Brown not because of the theft, but because Brown and a friend were blocking traffic. Wilson tried to exit his vehicle but Brown pushed him back into the car, according to a preliminary investigation, St. Louis County Police Chief Jon Belmar said.

Brown assaulted the officer while Wilson was in the car, and a shot was fired inside the police car during a struggle over the officer's gun, Belmar said.

Johnson disputes that, saying Wilson -- while sitting in the car -- started the scuffle by grabbing Brown by the neck, and that Brown tried to pull away. Johnson also said that there was no struggle for the gun, but rather that Wilson drew the weapon and shot Brown once at the car.

Johnson said Wilson shot Brown again as the teen ran away. According to Johnson, Brown was struck in the back and then turned around and put his arms up as the officer kept shooting.

The caller, who identified herself only as "Josie," said Brown -- after going away from the vehicle following the first shot -- turned around, taunted the officer and charged at him. Her account matches what Wilson has told investigators, a source with detailed knowledge of the investigation told CNN.

An autopsy showed Brown had six gunshot wounds.

Attorney Chris Chestnut told CNN this week he was surprised by the gap in shots.

"It's the pause that gives most concern in a police shooting, especially with an unarmed victim, because at this point Mr. Brown is defenseless -- he has no weapon," said Chestnut, who represented the family of Jonathan Ferrell.

Like Brown, Ferrell was an unarmed African-American man who was shot and killed by a white police officer. That incident occurred in North Carolina.

But if the gunfire heard on the audio is from the Brown incident, the pause doesn't automatically suggest wrongful intent by the officer.

"To be fair, there could be other explanations for that pause," said attorney Van Jones, co-host of CNN's "Crossfire." "Maybe the officer will say, 'Well, I fired and he kept advancing, so I fired again.' "