A former transit police officer who fatally shot an unarmed man at an Oakland train station was convicted of involuntary manslaughter Thursday, capping a racially charged case that raised fears in the Bay Area of possible violence after the verdict.

Prosecutors accused the former BART officer of intentionally firing his handgun as he tried to handcuff Oscar J. Grant III on New Year’s Day 2009.Johannes Mehserle, 28, tearfully testified that the shooting was a tragic accident caused when he mistakenly grabbed his firearm instead of an electric Taser weapon during a struggle with Grant.

The shooting was captured on video by several witnesses. Mehserle, who is white, fired a single round into the back of Grant, who was black and was lying face-down on the station platform. Mehserle resigned a week after the shooting.

The killing provoked protests and violence in Oakland. The case, which has drawn comparisons to the videotaped beating of Rodney G. King that ultimately triggered riots in Los Angeles in 1992, was moved to Los Angeles for trial amid concern about the extensive media coverage of the killing in the Bay Area.

Many civil rights activists considered the case a test of how the justice system treats police officers accused of abusing minorities. The trial also captured the attention of law enforcement officers who feared that a guilty verdict could raise the stakes for cops who make mistakes.

[Updated, 4:25 p.m.: Mehserle faces a minimum of five years and a maximum sentence of 14 years in prison, authorities said.

Aidge Patterson, a spokesman for the L.A. Coalition of Justice for Oscar Grant, called the verdict a "perversion of justice that seeks to absolve Johannes Mehserle in his cold-blooded killing of Oscar Grant."

Olis Simmons, executive director of an Oakland youth group that is advocating a peaceful reaction, called the verdict a miscarriage of justice.

"It is a walk for him. It is a walk," said the head of Youth UpRising. "I think everyone -- the family, every young black person who is afraid of the police -- everybody is going to see this as a miscarriage of justice."

She said federal prosecutors should file a civil rights case against the former BART officer.

"It doesn’t reflect well that we had an all-white jury, and it really leaves people feeling that his occupation and his race mattered more than the life of the young man. "

She said she feared there would be violence but she hoped "for the best."

Workers began leaving downtown Oakland shortly after 3 pm after receiving word that a verdict had been reached. BART trains were jammed, but the evacuation was orderly. Some business owners were seen putting plywood over their windows.]

-- Jack Leonard in Los Angeles, Maria L. LaGanga in Oakland and Maura Dolan in San Francisco