Gina Barton and Ashley Luthern of the Milwaukee Journal Sentinel reported the body camera footage will be released to the public Wednesday.
Milwaukee Mayor Tom Barrett told reporters Monday that he has "concerns" after watching the video.
"I'm going to let the release of that speak for itself, but yes, I definitely have concerns after watching that video," Barrett said.
Brown will be filing a civil rights lawsuit, claiming the officers used undue force. Sources who have seen the video told the Sentinel the body cam footage is "very bad" for the officers, who have yet to be publicly identified.
The Milwaukee Police Department said an internal investigation is ongoing, but no punishments have been announced. A civil lawsuit makes it much more likely details of the incident will be heard within the confines of a courtroom, barring a settlement.
Brown was charged only with a parking violation after originally being arrested for resisting or obstructing an officer. The incident left him with multiple bruises and scratches on his face. He has not publicly commented on the matter.