Authorities are now focusing on a Santa Monica apartment where ordnances had been recovered a day before the fatal explosion

Officers spent hours searching a Santa Monica apartment building where the device that exploded and killed three deputies may have originally come from.

A deadly explosion at a Los Angeles County Sheriff's Department training facility in Monterey Park resulted in the tragic deaths of three deputies. The incident, believed to be accidental, prompted a swift response from emergency services and the involvement of the FBI and Department of Homeland Security.