Trump calls for a surge of hundreds of federal officers in cities that have seen increases in violent crime

CHICAGOInside a modified freightliner parked on Chicagos west side this week, technician Jill Jacobson fired two rounds from a black 9mm pistol into a machine designed to capture the unique markings made on a bullet case as ammunition moves through a gun.
Just an hour earlier, a field agent with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives brought the weapon to the technology-laden truck, one of roughly 300 federal agents now in Chicago to help local police ramp up efforts to combat gun crime amid a sharp…