NEW : Police Lt. says crowds were vocal but orderly . Comment: Groups demonstrate about a transit officer who shot and killed an unarmed black man . `` Jail All Racist Killer Cops , '' proclaimed one large banner , held aloft by several people . Officer was found guilty of involuntary manslaughter in the shooting of Oscar Grant .
NEW : Police Lt. says crowds were vocal but orderly . Comment: Groups demonstrate about a transit officer who shot and killed an unarmed black man . Officer was found guilty of involuntary manslaughter in the shooting of Oscar Grant .