OAKLAND, Calif. -- Two members of BART's Board of Directors have called for the organization's general manager and the BART Police Chief to step down after KTVU broadcast the latest controversial video connected to the New Year's Day shooting of Oscar Grant.

The board members are demanding changes at the top, saying recently uncovered cell phone video of a BART police officer KTVU showed Friday night is the last straw.

"Unless there's something there you can't see, it looks like a clear case of police misconduct," said BART director Tom Radulovich.

BART director Lynette Sweet first saw the clip on the KTVU Channel 2 News as well: "It just wasn't brought to my attention. KTVU has pretty much been my information source."

Exclusive cell phone video KTVU obtained appears to show a BART police officer go to where a woman officer is talking to three other men and punch one in the face. That man we now know was Oscar Grant. Grant and the others sit down as the same officer appears to aim a Taser gun at them.

"If I just walked up to you and just hit you for no good reason, I'd go to jail," said Sweet. "I don't think we need to act like our police officers are above the law."

A few minutes later, two other officers arrive and Officer Johannes Mehserle shoots Oscar Grant in the back, killing him. Mehserle's now charged with murder. The officer who appears to hit Grant in the face -- and investigators say has his knee on Grant's neck during the shooting -- is not charged with anything.

Sources identify the second officer as Tony Pirone. Before KTVU aired the video, BART's police chief repeatedly said BART's investigation found that no officer but Mehserle did anything improper.

BART Board member Radulovich says he's particularly troubled that the $25 million wrongful death claim filed against BART a few days after the New Year's Day shooting says "an officer kneed him [Grant] in the face. And yet, Radulovich says, apparently BART investigators missed the punch and officers didn't report it.

"You wonder what happens in incidents when there isn't video," explains Radulovich. "Is the internal investigation good enough? I think we need some change at the top."

Radulovich wants BART's General Manager Dorothy Duggar to resign. His colleague Lynette Sweet is calling for the ouster of BART Police Chief Gary Gee.

"I am asking for the chief's resignation. I think as it stands right now the BART police force has operated in a way I can't trust," said Sweet.

Those two BART directors say they have not polled the seven other members of the board, but believe there is growing momentum to restore confidence in BART by making some changes at the top.