BART Cop Shooting of Oscar Grant

I've recently been following the story unfolding in the shooting of Oscar Grant.  From the live videos shot by passengers on the trains of San Fransisco (known as BART), it looks like an unprovoked assault and murder of an unarmed African American passenger.  It just doesn't get a lot worse than that.  The shooting was supposed to be a mistake, but I really think that makes very little difference, after viewing the video.  Mr. Grant was clearly being abused no matter what the situation, and if he had been shot with a taser gun, Officer Mehserle should still be in jail.  That our justice system has allowed him bail is atrocious.  That the officer with his knee on Grant's neck was not charged is absurd and revolting.  That any of this even began to happen shows that San Francisco police are not trained well and there are some who ought to be weeded out.