Los Angeles defends school closure over email threat

Los Angeles city officials on Tuesday defended their decision to shut down all public schools following an emailed threat, as authorities in New York dismissed a similar message as a hoax. Ramon Cortines, the superintendent of Los Angeles schools -- the second-largest education district in the United States with 640,000 students -- said the measure was ordered as a precaution, triggered in part by the December 2 attacks in nearby San Bernardino that left 14 people dead. "In an abundance of cauti