The device that exploded last week at a LASD facility and killed three detectives was a grenade, ABC News sources confirmed.

Authorities are looking into whether grenades recovered from a Santa Monica apartment complex caused an explosion last week at a Los Angeles County Sheriff’s Department training facility that killed three members of its arson and explosives unit.

Serving the search warrant were sheriff’s homicide investigators, the Bureau of Alcohol, Tobacco, Firearms and Explosives, and the Los Angeles Police Department. It was unclear exactly where the