The FBI has questioned a man who says he recorded audio of gunfire at the time Brown was shot by Ferguson police on August 9, the man's attorney told CNN.

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.  

"I was very concerned about that pause … because it's not just the number of gunshots, it's how they're fired," the man's attorney, Lopa Blumenthal, told CNN's Don Lemon. "And that has a huge relevance on how this case might finally end up."

18-year-old Michael Brown was killed when police officer Darren Wilson shot him after stopping Brown in the street. Exactly what happened in-between their first interaction and Brown's death is still unclear, but this new information seems to contradict claims by Wilson supporters that the deadly force used against Brown was justified. 

Brown was laid to rest Monday afternoon. Thousands attended the funeral of the young man whose death has sparked a national uprising.