When a BART police officer shot Hayward resident Oscar Grant after a struggle on New Year's Day, the BART security cameras weren't recording, and no one had a filmed account of what really happened. But it turns out that one of the witnesses filmed the event and gave a copy to KTVU. The film, the Chron reports, apparently shows cops throwing Grant to the ground and trying to cuff him while he struggled. Then one officer stopped applying the cuffs, drew his weapon, and shot him in the back as he lay face-down on the ground. Another witness claims that Grant, who worked at a market in the Dimond District, pleaded with cops not to shoot him, and added that he had a daughter. BART officials are reportedly trying to determine whether the officer thought he was reaching for his taser when he drew down on the young man. In the meantime, they are pleading with the public to remain calm while the investigation proceeds. Oakland attorney John Burris has already announced that he plans to file a $25 million lawsuit on behalf of Grant's family.