Multiple people were killed Friday after an explosion rocked a Los Angeles County Sheriff’s Department compound where the agency’s arson explosive detail and bomb squad are based. The blast was reported at the Biscailuz Center Academy Training facility in East Los Angeles at about 7:30 a.m., KTLA reported. Three deputies are believed to have died, sources told the outlet. Authorities have not said what caused the blast, but law enforcement sources told the LA Times that a bomb squad had been moving explosives around that time. Aerial footage from local news helicopters appeared to show a sheriff’s vehicle inside the complex with its rear windshield broken.