Aliso Viejo Explosion: Fatal Blast in California Likely Not an Accident, Authorities Say

The explosion at a building in Aliso Viejo, California, on Tuesday, was being investigated as a crime, the Orange County Sheriff's Office said in a press conference Wednesday afternoon. One person was killed and three others injured in the blast.

"We do not believe at this time that this was an accident," a representative for the sheriff's office said at a press conference. "We have ruled out the potential that this was an accident."

The explosion occurred around 1:10 p.m. local time at what authorities said was a day spa, some 50 miles south of Los Angeles. Based on a preliminary investigation, authorities said they think the victim was the owner of the spa and may have been targeted. In addition, investigators said they recovered materials at the scene that led them to believe it was not an accident. The items were sent back to the FBI laboratory in Quantico, Virginia, for testing, and police would not comment on the specifics of what they found.

"At this point, our working theory is that this explosion was caused by a device," FBI officer Paul Delacorte said Wednesday. "There are some components we have located at the scene that are inconsistent with what one might expect to find at this business."

Witnesses spoke of a loud crash and said they saw two women who had been burned in the explosion come out of the building. Surrounding areas, including a nearby preschool, were evacuated. The premises of the facility was swept after the explosion to ensure there were no devices that could cause a secondary explosion.

The Orange County Sheriff's Office, the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosions continued to investigate. A motive had not yet been determined and no arrests had yet been made in connection with the explosion.