The petition submitted by ColorofChange.org alleges that BART officer Tony Pirone "appears to have committed a serious crime" by punching Grant, a 22-year-old Hayward man, shortly before officer Johannes Mehserle shot and killed Grant at the Fruitvale station in Oakland early on New Year's Day.
The racially charged trial of a white transit officer accused of killing an unarmed black man focused Tuesday on training procedures, with two weapons experts showing jurors proper techniques for handling guns.
The testimony was meant to illustrate possible factors involved when ex-Bay Area Rapid Transit police officer Johannes Mehserle, 28, shot Oscar Grant on New Year's Day 2009 in Oakland.
Mehserle has pleaded not guilty to murder.
Defense attorney Michael Rains has said Mehserle meant to pull out his Taser stun gun instead of his .40-caliber handgun before he shot the 22-year-old Grant.
Sgt. Paul Garcia, a rangemaster for the transit agency, used a blue plastic gun to show jurors how a weapon should be removed from the holster used by Mehserle.
An officer would have to push down and forward on a holster hood then pull back a lever to release the gun, Garcia said.
David Clark, a rangemaster at a police academy at Napa Valley College, said officers learn during training how to unholster guns, hold weapons and take note of their surroundings when they shoot at a target.
"It takes a long time to build up muscle memory," he said. "It has to be practiced over and over and over."
On cross-examination, Rains showed video footage to Clark, who indicated Mehserle didn't appear to follow proper training techniques by shooting Grant in close proximity to another transit officer and by putting his gun back into his holster after firing it.
Clark added that if Mehserle felt threatened and decided to use his gun, "he should have shot from a kneeling position."
Rains said in his opening statement that Mehserle told fellow transit officer Tony Pirone before the shooting, "Tony, Tony, Tony, I can't get his hands. I'm going to tase him."
The stun gun has a switch that must be pushed upward to charge the weapon.
Mehserle resigned shortly after the shooting. Pirone was fired in April.
In other developments, a female juror was excused after Superior Court Judge Robert Perry said she had trouble staying awake during testimony. A man replaced her on the panel that now has seven women and five men.
Another female juror was excused last week for cause, but Perry declined to elaborate. Four alternates remain.