OAKLAND — Nearly 1,000 people filled the street in front of Oakland City Hall on Thursday evening. They gathered to vent, pray, and ask how a Los Angeles jury could find Johannes Mehserle, a white former BART police officer, guilty of involuntary manslaughter for fatally shooting Oscar Grant III, an unarmed, 22-year-old black man from Hayward, in the back.At first, the crowd was electric, but not volatile. To respond with violence would dishonor Grant's memory, they said. Hundreds of Oakland police officers watched and endured taunts, spits and rocks from a small group that tried, but failed, to incite other...