The grainy videos of the killing have been played over and over in a Los Angeles courtroom.
On two large television screens, a white transit police officer is shown reaching for his holster as he struggles with a black man lying face-down on an Oakland train station platform. The officer draws his handgun and fires a single bullet into the man's back.
The images, captured by witnesses, lie at the center of a rare criminal trial in which a police officer is charged with murder for an on-duty shooting. The jury, which could begin deliberating as early as this week, must decide whether the shooting was intentional or, as the officer contends, a tragic mistake.
The footage has shaped the racially charged case from the beginning and has drawn strong comparisons with the videotaped beating of Rodney G. King that ultimately triggered riots in Los Angeles nearly two decades ago.
Like the King case, the New Year's Day 2009 shooting of Oscar J. Grant III provoked outrage and fueled debate about race and police abuse. It unleashed angry protests and violence in Oakland, where minority fears of police brutality have historically run deep.
Excerpts of videos taken by train passengers have been broadcast countless times by Bay Area television news stations. The trial was moved to Los Angeles amid concern about the extensive media coverage.
"The thing that was significant about the Rodney King case was that it was there for all the world to see. That's the same with this case," said Robert C. Smith, a political science professor at San Francisco State. "People have a sense that they saw it, that they were a witness to it."
More than a year later, emotions still run high.
Oakland police and city leaders fear the possibility of violence when a verdict is announced.
Last week, the city's Police Department simulated a riot to help officers prepare for unrest. Meeting areas are being set up for residents to peacefully express their feelings about the verdict. And preachers have agreed to urge calm.
"Whatever the verdict, it's sure to raise a lot of emotion. It touches an issue that's very deep in the community," said city spokeswoman Karen Boyd.
A spokesman for the Los Angeles Police Department said special preparations were in the works for any post-verdict crowd gathering outside the downtown criminal courts building, but he declined to elaborate.
"We are not going to go into any sort of detail on our planning other than to confirm that we are working with court security and are prepared to handle any gathering of crowds outside of the courthouse when a verdict is returned," said Lt. John Romero.
The shooting happened before dawn as Bay Area Rapid Transit police responded to reports of a fight on a train packed with New Year's Eve revelers. Several passengers in the train, which was stopped at the Fruitvale Station, began recording the events on video as a police officer appeared to manhandle Grant, 22, and a group of his friends.
Among the BART police officers who arrived to help was Johannes Mehserle, a 6-foot-4-inch, 250-pound cop who had been on the job less than two years.
Alameda County prosecutors allege that Mehserle, then 26, fired the fatal shot deliberately after an ugly confrontation between Grant and a fellow officer. Grant, a grocery store butcher, was unarmed.
Mehserle told jurors that he intended to use an electric Taser weapon on his belt during a struggle to handcuff Grant but mistakenly drew his handgun.
The case has drawn strong interest from police officers around the state who are concerned that prosecutors overreacted to a tragic but honest mistake, said Ron Cottingham, president of the Peace Officers Research Assn. of California. A murder conviction, he said, could have a ripple effect on how officers respond to threats in the field.
"Any time you have to use deadly force, it's going to cause you to pause. And you don't have a lot of time to pause," said Cottingham, whose group's legal defense fund is paying for Mehserle's defense.
The start of the trial stirred controversy earlier this month when no blacks were selected for the jury. The five-man, seven-woman panel is made up of seven whites, four Latinos and a man who declined to identify his race on a questionnaire.
Courtroom security has been tight. Each morning, jurors gather at a secret location and are taken as a group by bus to the courthouse, a court spokesman said. They eat lunch in a back room and are returned to the same undisclosed location at the end of the day's testimony.
For more than two weeks, jurors have been shown scenes from the station platform numerous times from multiple angles. Each side argues that the videos support its account of what caused the shooting.
The prosecution contends that the recordings are powerful evidence of police officers creating "chaos, distrust, disorder."