A former Philadelphia police officer has been charged with murder and is being held without bail for fatally shooting an unarmed 12-year-old boy named Thomas Siderio in March. Philadelphia District Attorney Larry Krasner accused the officer, Edsaul Mendoza, of shooting the 12-year-old while the boy was face down on the sidewalk after a foot chase. Prosecutors say the 12-year-old had fired a gun at one point but had discarded it about 40 feet away from where he was shot.