KANSAS CITY, Mo. (AP) — Federal authorities argue that new state law forbidding local police from enforcing federal gun laws is hampering efforts to protect the public. A blistering court brief filed Tuesday by the U.S. Department of Justice outlines multiple examples. The brief said that after an Independence police officer was killed in a shootout in September, Missouri state law enforcement initially refused routine federal assistance in tracing the murder weapon. The Department of Justice says the Missouri state crime lab, operated by the Highway Patrol, also is refusing to process evidence that would help federal firearms prosecutions.