LOS ANGELES -- A white former transit officer was convicted of involuntary manslaughter Thursday in the shooting death of an unarmed black man on an Oakland train platform in a 2009 encounter that set off days of rioting in the city.
Grant's mother, Wanda Johnson, stared at jurors and appeared upset then later denounced the verdict outside the courthouse.
"My son was murdered! He was murdered! He was murdered," she said.
Earlier in court, Mehserle was placed in handcuffs and taken away after the verdict, which included a finding that the defendant personally used a handgun. He turned to his family and mouthed, "I love you, guys." His parents wept when the verdict was read.
One woman juror wiped tears with a tissue when the panel was polled on its decision.
On the east side of San Francisco Bay, police in riot gear were deployed on the streets of Oakland.
A crowd near Oakland City Hall moaned and cursed when they heard the verdict. A dozen people gathered in a semicircle to pray.
"It's not real, it's not real. Where's the justice? He was killed in cold blood," said Amber Royal, 23, of Oakland.
Grant family attorney John Burris said the family was "extremely disappointed" with the verdict.
"This verdict is not a true representation of what happened to Oscar Grant and what happened to him that night. This was not a voluntary manslaughter case," Burris said.
Gov. Arnold Schwarzenegger issued a statement urging Californians to remain calm and not resort to violence. Schwarzenegger said he had informed Oakland Mayor Ron Dellums the state was well prepared to assist in maintaining order.
The jury had a choice between murder and lesser charges of voluntary and involuntary manslaughter. The jury found that Mehserle didn't mean to kill Grant, but that his behavior was still so negligent that it was criminal.
Involuntary manslaughter carries a sentence of two to four years. The next hearing was set for Aug. 6.
The jury included eight women and four men. None listed their race as black. Seven said they were white, three were Latino, and one was Asian-Pacific. One declined to state their race. They left the courthouse under tight security.
"As we have come to notice, and we as a family has been slapped in the face by a system that has denied us a right to true justice," said Cephus Johnson, Grant's uncle. "We truly do not blame the jury, but we blame the system."
At least five bystanders videotaped the New Year's Day incident in what was among the most racially polarizing cases in California since four Los Angeles officers were acquitted in 1992 in the beating of Rodney King.
The case was a rare instance in which a police officer stood trial for an on-duty killing and that was captured on video from so many different angles.
Legal experts said the verdict shows the jury sympathized with Mehserle's version of events.
"It is legally as low as they could go without acquitting him," University of California, Berkeley, law school professor Erin Murphy said. Prosecutors had a "huge hurdle" to overcome in convincing a jury that an officer with a spotless record meant to kill, even with video of the killing, she said.
"I think it's a lesson that video can only get us so far," Murphy said.
Santa Clara University law school professor Edward Steinman added that jurors probably believed Mehserle's story that he made a mistake.
The verdict followed a three-week trial in which prosecutors played videos by bystanders, and witnesses recounted hearing the frightening gunshot that killed Grant.
Mehserle, 28, testified that he struggled with Grant and saw him digging in his pocket as officers responded to reports of a fight at a train station. Fearing Grant may have a weapon, Mehserle said he decided to shock Grant with his Taser but pulled his .40-caliber handgun instead.
Alameda County Deputy District Attorney David Stein said in his closing argument that Mehserle let his emotions get the better of him and intended to shoot Grant with the handgun without justification.
One of Grant's friends, Jackie Bryson, testified that Mehserle said "(expletive) this" before firing the fatal shot.
Defense attorney Michael Rains contended the shooting was a tragic accident. Mehserle had no motive to shoot Grant, even though he was resisting arrest, the lawyer argued.
Rains also said Mehserle told a colleague before the shooting: "Tony, Tony, Tony, I can't get his hands. I'm going to tase him."
Mehserle pleaded not guilty to murder and resigned from the Bay Area Rapid Transit agency after the shooting.
Fallout from the shooting was swift in Oakland after the videos were shown on television and the Internet. The shooting and the nearly two weeks it took to arrest Mehserle sent the city into a tailspin of violence as downtown businesses were damaged, cars were set ablaze and clashes erupted between protesters and police.
Grant had recently been released from jail after being sentenced to 16 months for a gun possession charge filed after he ran from police and was subdued by an officer with a stun gun.
Grant has become a martyr of sorts in a city where more than a third of residents are black. His omnipresent image on buildings and storefront windows arguably rivals that of slain hometown rapper Tupac Shakur.
Grant's family and friends filed multimillion dollar lawsuits against the transit agency. Only the mother of Grant's daughter has reached a settlement.