Another police officer’s brutality set the tone that led to the fatal shooting of a young Black man at an Oakland, Calif.-area metro station on New Year’s Day, a newly released video reveals.

The Bay Area Rapid Transit Police Department said initially that only Officer Johannes Mehserle was involved in shooting to death 22-year-old Oscar Grant as he lay on the ground with his hands behind his back.

But the new video shows Officer Tony Peroni punching Grant just minutes before the shooting, the San Francisco Chronicle reports.

"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 the attorney representing the Grant family.

BART officials have promised a new investigation into Grant’s shooting, given the new video.