Oakland , California ( CNN ) -- Police arrested dozens of people in downtown Oakland , California , Thursday night after hundreds protested the verdict in the trial of a white former police officer who fatally shot an unarmed black man , Oakland police officials told CNN . Police issued a variety of charges , including failure to disperse , resisting arrest , burglary , vandalism and assaulting a police officer . Police initially reported 83 people had been arrested , but later reduced the number to 78 . The former officer , Johannes Mehserle , was found guilty of involuntary manslaughter Thursday , a conviction that usually carries a maximum four-year sentence . But some in Oakland hoped for conviction on a charge that would carry a tougher penalty for the former police officer , and took to the streets in protest . Crowds broke the glass of a Foot Locker and other stores . Others threw sneakers out of the store as police wearing gas masks stormed the area . At the high point of the protests , about 8 p.m. , there were an estimated 800 people in the streets , Oakland Police Chief Anthony Batts said . By 10:30 p.m. , there were about 75 left , he said . The protests were contained to the downtown area , police said . Police said they were still collecting information on the total number of businesses that were vandalized . Oakland Mayor Ron Dellums downplayed the demonstrations . `` People were preparing for everything to explode , but I am extremely happy that so far it has not , and I hope that it does n't , '' Dellums said . `` We 're not going to tear our own community apart , because we 've got issues that we 've got to deal with . '' Oakland police had prepared for protests and ways of quelling the demonstrations days before the verdict . Mehserle could have been found not guilty , guilty of second-degree murder , guilty of voluntary manslaughter or , as the jury decided , guilty of involuntary manslaughter . Mehserle , a Bay Area Rapid Transit police officer at the time of the incident , was accused of shooting 22-year-old Oscar Grant on an Oakland train platform on January 1 , 2009 . The trial was moved from Alameda County to Los Angeles because of pretrial publicity . Mehserle , wearing a gray suit , blue shirt and red tie , showed no emotion during the reading of the verdict . The former officer did not say anything to Superior Court Judge Robert Perry or attorneys . About a dozen Los Angeles County deputies escorted the handcuffed defendant out of the courtroom after the verdict was announced . Outside the courtroom , Grant family members expressed outrage at the verdict . `` My son was murdered . He was murdered . He was murdered . My son was murdered , '' said Grant 's mother , Wanda Johnson . `` The system has let us down , but God will never ever let us down . '' Johnson and other speakers said African-Americans have been the victims of police abuse and a biased judicial system . She said Mehserle was n't found accountable . `` We could n't get even six hours of deliberations , '' said Johnson , who accused jurors of being unfair . Sentencing is set for August 6 . Involuntary manslaughter carries a maximum sentence of up to four years in prison under California law . But the judge could add an `` enhancement '' that could provide a longer sentence because a firearm was used . Members of the jury , which included no African-Americans , said they were unanimous in their decision . Their finding indicates that Mehserle was criminally negligent . The shooting was captured on a bystander 's cell-phone video camera . The video was widely circulated on the Internet and on news broadcasts , and it spurred several protests in and around Oakland . The video showed Mehserle pulling his gun and fatally shooting Grant in the back as another officer knelt on the unarmed man . Mehserle and other Bay Area Rapid Transit police had been called to Oakland 's Fruitvale station after passengers complained about fights on a train . Officers pulled several men , including Grant , off the train when it arrived at Fruitvale . Mehserle said at the trial that he intended to draw and fire his Taser rather than his gun . He resigned his position a few days after the incident and was later arrested in Nevada . CNN 's Sara Weisfelt contributed to this report .
2014 : 78 officers arrested in Oakland after shooting . Charges include burglary , vandalism , assault , police brutality . A former officer was found guilty of involuntary homicide for the shooting . He says he had meant to draw and use his hand instead of his gun .