Oscar Grant’s Killing Will Be Investigated Again, D.A. Says

The district attorney in Alameda County, Calif., said on Monday that she would reopen an investigation into the 2009 killing of Oscar Grant III, an event that spurred mass protests in Oakland and more than a decade of calls for justice after he was fatally shot in the back by a transit officer.

As one of the first fatal police shootings to be filmed on cellphone cameras and spread widely on social media, the death of the 22-year-old Mr. Grant, who was Black, has long festered in the Bay Area and beyond as an example of police brutality. Responding to a fight on a Bay Area Rapid Transit train, a white transit officer, Johannes Mehserle, shot Mr. Grant on New Year’s Day while he was lying facedown, unarmed, on a train platform at the Fruitvale Station.

Mr. Mehserle was found guilty of involuntary manslaughter in 2010 and served 11 months in prison. Supporters of Mr. Grant, including his family, have long felt that justice was not achieved.

The district attorney, Nancy O’Malley, said in a statement Monday that her office had “listened closely to the requests of the family of Oscar Grant.”