Authorities investigating the deadly blast at a Los Angeles County Sheriff's Department training facility are looking into connections to some explosives collected in Santa Monica.

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.

Three deputies with the Los Angeles County Sheriff’s Department were killed Friday morning after an explosion occurred at a department facility in East Los Angeles, marking the agency’s deadliest day in more than 165 years.