Is it possible that somebody came into the frame and was speaking...but that audio has been removed...and this is why the video was altered.
Yes its wild speculation...but the video is clearly edited. I wish these dashcams and body cams were instantly uploaded to site that could be accessed by a third party. Keeping the police as the gatekeepers fosters distrust...especially when they doctor video like this.
Have you watched the video at the link ? There may have been some irregularities/edits in an earlier release. Whatever those may have been, at least those noted in the link in the thread topic, are not present in the (shorter by 3 minutes) footage now available.