A police officer puts up yellow tape near the offices of Los Angeles Unified School District (LAUSD), in Los Angeles, the United States, on Dec. 15, 2015. All LAUSD schools will stay closed today in response to a reported bomb threat, Schools Superintendent Ramon Cortines said. Police said the threat was called in to a School Board member. The threat is involving backpacks and packages left at campuses. The closures applied to all LAUSD campuses, around 900 of them. Los Angeles Unified School District is the second-largest school district in United States, which has more than 700,000 students.