These heroes represented the best of our department, exemplifying courage, integrity and selfless service," Los Angeles County Sheriff Robert Luna said in a statement

Three veteran Los Angeles County Sheriff’s Department members assigned to the agency’s arson and explosives detail were killed Friday morning by an explosion at a department training facility, according to Sheriff Robert Luna.

The mass casualty incident is the department's deadliest day since 1857 and has led to an outpouring of grief from law enforcement officials across the nation