The authorities said Kevin O’Neal tried to set off explosives as Polk County, Tenn., deputies entered his home. More than a dozen devices were later found.
He funneled cash and weapons to the Irish Republican Army from Libya, and was involved in bombings that targeted Margaret Thatcher and others, killing scores of people.
Many of the blasts, some of them deadly, have been at weapons storage sites, raising questions about whether ordnance from Syria’s civil war has been properly secured.
Officials were looking into whether the explosion, which killed three sheriff’s deputies, was caused by devices seized from a condo in Santa Monica a day before the blast.
It was not immediately clear what caused the blast at the Los Angeles County Sheriff’s Department’s Biscailuz Training Academy center. No one else was injured, officials said.