The FBI says the investigation into a deadly building explosion in Southern California has led to the arrest of a man on suspicion of possession of an unregistered destructive device.

FBI spokeswoman Laura Eimiller stresses in a statement Thursday that the subject, 59-year-old Stephen Beal of Long Beach, has not been charged in connection with Tuesday's explosion.

Beal's Facebook page shows many photos of him apparently recently traveling with the woman who was killed, 48-year-old Ildiko Krajnyak, a cosmetologist who ran a day spa at the building hit by the blast.

Beal is expected to make an appearance in federal court Thursday afternoon.

Eimiller says no additional details will be provided until a federal criminal complaint is released.

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