SAN FRANCISCO -- The U.S. Department of Justice's civil rights division will investigate a white former transit officer who was convicted in state court of killing an unarmed black man - a verdict that touched off angry protests and more than 80 arrests in Oakland.
In a move reminiscent of the Rodney King beating case in Los Angeles, the federal government said it intends to investigate Johannes Mehserle, who was found guilty Thursday in state court of involuntary manslaughter in the death of 22-year-old Oscar Grant.
The federal investigation could expose him to even more prison time if the Department of Justice charges him with violating the rights of Grant.
Two police officers convicted in federal court of rights violations in the King beating were each sentenced to 2 1/2 years in prison. Any possible federal prison sentence for Mehserle likely would be served after a state term.
Mehserle, 28, testified during his trial 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. Grant was shot as he lay face-down.
The jury found that Mehserle didn't mean to kill Grant, but that his behavior was still so negligent that it was criminal.
The verdict enflamed emotions in Oakland, where at least a dozen businesses were damaged after the jury reached its decision in Los Angeles.
Protesters looted an athletic footwear store and ransacked a jewelry shop. The windows of a bank were smashed, fires were set fires in several trash bins, and a small incendiary device was detonated near a police station but caused no damage.
Police said they made 83 arrests throughout the night for violations that included failure to disperse, vandalism and assaulting a police officer.
Graffiti on one building declared, "Oakland is our amusement park tonight!" Cleaning crews began sweeping up broken glass and debris early Friday.
"This city is not the wild, wild West," Oakland Police Chief Anthony Batts said. "This city will not tolerate this sort of activity."
The trial of Mehserle, who resigned from the Bay Area Rapid Transit agency after the shooting, was moved to Los Angeles following rioting in Oakland after Grant was killed on New Year's Day 2009. The latest demonstrations appeared to be much less severe, even though police did not immediately release a damage estimate.
In Washington state, vandals smashed the windows of a patrol car parked outside a Tacoma police officer's home and spray-painted the words "Oscar Grant was here" on the car.
Federal officials planned to begin their civil rights investigation after the conclusion of the state case against Mehserle, who faces sentencing Aug. 6.
Involuntary manslaughter convictions call for two to four years in prison. But since the jury also found Mehserle used a gun during the crime, the judge could tack on an additional three to 10 years – an option Oakland officials hope would quell additional unrest in the city.
The judge also has the option of tossing out the gun enhancement, though experts say that seems unlikely.
Legal experts also said a sentence of probation appears remote, especially since Mehserle was taken into custody immediately after the verdict and booked into the Los Angeles County Men's Central Jail, where he will be kept apart from the general population.
Mehserle was arrested two weeks after the shooting and has remained free after posting $3 million bail in February 2009, meaning he would have no credit for time served if he is sentenced to prison.
The U.S. Justice Department will conduct its investigation with the U.S. attorney's office in San Francisco and the FBI, said spokesman Alejandro Miyar, who declined further comment.
The department stepped into the Rodney King case after a state court jury acquitted four Los Angeles police officers in 1992 of using excessive force, touching off three days of riots, 53 deaths and more than $1 billion in damage.
A federal jury acquitted two of the officers of rights violations.
Some legal experts questioned whether an on-duty police officer should be punished with additional state prison time for using a service weapon. The gun enhancement law was passed to additionally punish armed muggers, robbers and other criminals for endangering lives during their crimes.
Using it in a shooting death that resulted in an involuntary manslaughter conviction is redundant and illogical, said Stanford University law professor Robert Weisberg.
Weisberg said it appears the jury believed Mehserle's testimony that he thought he was using his Taser when he shot Grant.
"There is a real ambiguity here," Weisberg said. "This is an odd application of the statute."
Risling reported from Los Angeles. AP Writers Trevor Hunnicutt in Oakland and Thomas Watkins in Los Angeles also contributed to this report.