In newly found video of the incident, Oscar Grant is clearly assaulted by a second BART cop just minutes before he is shot and killed by Johannes Mehserle.
Sources have identified that officer as Tony Pirone. He and the other officers present at the time of Grant's shooting all remain on paid administrative leave while the investigation continues, but until Saturday BART was not investigating the conduct of anyone besides Johannes Mehserle, 27, who shot Grant.
An analyst in the video suggests that Pirone's violence cold be blamed for escalating the tension in the situation which preceded Mehserle's shooting of Grant.
Peter Keane, a professor at Golden Gate University Law School and police expert, said Saturday night the video shows a "vicious, unprovoked and inexcusable assault" by the other police officer that should be prosecuted and that seems to have set off events that led to the shooting.
"With that powerful punch, he slams Mr. Grant in the side of his head and knocks him down even though it doesn't appear Grant is doing anything but talking - maybe he is mouthing off but there was no physical provocation," Keane said. "Why is the other officer not being prosecuted? It was a clearly a deliberate, abusive use of force."
This is another major blow to the BART police's ability to defuse the uproar over this story which has quickly become the most volatile case of police violence in California since the fabled Rodney King case.
See more discussion of the back-story in BentLiberal's recommended diary here. Also, discussion about the raw video footage of this incident began on dKos in Adept2u's diary last Wed. The reason this is front-page breaking news of SFGate.com is that today BART officials said "that they will investigate the actions" the punching officer (Pirone). The KTVU interviews with scholars are also new.
Another recommended diary by iliketodrum shows the protests in Oakland that began once the shooting video went viral. And if you have yet to see the original, and very disturbing, videos of the shooting, you will find them in LatinoDem's recommended diary here.
Some video transcript:
Peter Keane, UC Hastings Law School Professor:
"There's no question in my mind that that's vivid, powerful evidence that he committed a vicious, powerful assault unprovoked on a citizen for absolutely no reason. Wow. That's quite a shot. That office is committing a crime. That's a pretty brutal punch there. It just sends his head back and sends him to the ground. The District Attorney is saying he's not going to charge any officer except Mehserle. In my opinion, he's not doing his job. "
Franklin Zimring, UC Berkeley Boalt Law School professor:
"Unless there's something we don't see, then the degree of force that was used, and the way it was used, are not justified. Police officers are not, but virtue of their legal status, immunized from the normal laws that govern when there is illegal conduct. This is disturbing. The shooting and killing were more than disturbing."
Both men are considered experts on police practices.
The officer (Pirone) seen punching Grant, who also has his knee on Grant's neck during the shooting, is not charged with anything.
UC Hastings Law School Professor, Peter Keane, says the officer who threw the punch should be booted off the force and charged with civil rights violations.
The attorney representing the family of Oscar Grant says he was already aware of the video and says he blames the assaulting officer for escalating the response.
Attorney John Burris:
"His aggressiveness then caused the other officer to be aggressive, I believe. And that aggressiveness ultimately lead to the shooting. If he didn't have that level of conduct, I don't believe the shooting would have taken pace."