Los Angeles ( CNN ) -- A former transit police officer convicted last year in the shooting death of an unarmed man on an Oakland , California , train platform was freed from prison early Monday morning , the Los Angeles County Sheriff 's Department said . `` He was released at 12:01 a.m. , '' said spokesman Steve Whitmore . Johannes Mehserle was sentenced to two years in prison for the involuntary manslaughter conviction , but California law gave him one day of good conduct credit for each of the 365 days he served behind bars , Los Angeles Superior Court Judge Robert Perry said in a court order he signed last week . Mehserle has been behind bars since a Los Angeles jury found him guilty on July 8 , 2010 . Mehserle , a Bay Area Rapid Transit police officer when the shooting occurred , said at the trial that he intended to draw and fire his Taser rather than his gun when he fatally wounded 22-year-old Oscar Grant on New Year 's Day 2009 . Violent protests erupted in Oakland last November when Perry sentenced Mehserle to just two years in prison , which meant he could be released after another seven months . At least 150 people were arrested during the protests , which Oakland Police Chief Anthony Batts described at the time as `` tearing up the city . '' See damage caused by protesters . Grant 's mother , Wanda Johnson , had asked the judge to sentence Mehserle to the maximum 14 years in prison . She and four other family members who spoke at the sentencing hearing last year called him `` a murderer . '' The jury acquitted him of the more serious charges of second-degree murder and voluntary manslaughter . Although his defense attorney argued for probation , Mehserle told Perry before sentencing that he would be willing to go to prison if the sentence made his city and family safer . `` I shot a man , '' he said . `` I killed a man . It should not have happened . '' A conviction for involuntary manslaughter can carry a sentence of four years , but the judge had the option of adding an `` enhancement '' that could have made the sentence 14 years because a firearm was used in commission of a crime . CNN 's Rick Martin , Alan Duke and Greg Morrison contributed to this report .
Johannes Mehserle walks out of prison early Monday . The former BART officer was convicted of involuntary manslaughter in Oscar Grant 's death . Mehserle served one year of a two-year sentence because of credit for good conduct .