California building explosion may have been parcel bomb attack, investigators fear

One woman killed and three injured after 'suspicious' blast

This image taken from cellphone video shows a building after a fatal explosion in Aliso Viejo, California, 15 May (AP)

Police and federal officials are investigating after a woman was killed and three other people injured in an explosion at a medical office in California.

The blast happened at about 1pm local time on Tuesday in Aliso Viejo, some 50 miles south of Los Angeles.

“The whole bottom floor is pretty much blown out,” fire brigade captain Tony Bommarito said.

The size of the explosion was suspicious, officials said, with one federal agent suggesting it may have been caused by a parcel bomb.

However, authorities said they had not yet found any explosive devices.

Bomb technicians and agents from the Orange County Sheriff’s Department, the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives were at the scene Tuesday night.

“We have not found any type of specific device inside of the building right now that would tell us or lead us to exactly what the device was, if there was a device,” sheriff’s department commander Dave Sawyer said.

The woman who was killed inside the building was “in close proximity” to the explosion, Mr Sawyer said. The three people who were injured were nearby and were being questioned by investigators late Tuesday night, he said.

“Anytime you see an explosion of this magnitude, it would definitely be suspicious to us,” Mr Sawyer added.

Authorities were not searching for any specific suspects on Tuesday night, but the investigation was continuing, he said.

Mary McWilliams told The Orange County Register she arrived for an appointment to find smoke surrounding the area and car alarms going off.

McWilliams said she saw two burned women staggering out of the building, covered in ash and soot.

One woman, who had skin peeling on her arm from burns, said, “Take care of my mother,” Ms McWilliams said. The other woman was bleeding from her head.

Fire officials said a third person suffered smoke inhalation.

A daycare centre and pre-school on the other side of the road was evacuated. Some children held hands as they were led out by firefighters while sheriff’s deputies rolled out babies in cribs.

No children were hurt.

Additional reporting by AP