Prior to the release of the new BART Police Chief Gary Gee told reporters BART was not investigating the conduct of any other officer except for Mehserle.
During a January 12th press conference Gee told reporters, "All the other officers who responded to the incident at around 2 a.m. at Fruitvale Station followed protocol. They performed their duties in a professional manner."
But, the attorney representing Grant's family says the actions by the first officer set the tone for what happened next.
"That officer is the one that was aggressive, more aggressive than was necessary, and ultimately created the environment for the shooting to take place. Because, if he had not done that Mr. Grant would have still been seated against the platform and the officer would not have been in position to shoot him in the back," said Grant.
The new video is one of several that have emerged since the deadly shooting.
The person seen pulling the trigger, BART officer Johannes Mehserle, has pleaded not guilty to murder. He also resigned from the force.
The officer who appears to be punching Grant has been identified by the Chronicle as Tony Peroni.
The question now is whether or not he DA will press charges against him
ABC7's efforts to get a response from BART went unanswered Sunday.