LONG BEACH, Calif. (KABC) -- Long Beach man Stephen Beal has been arrested in connection with the fatal 2018 explosion in Aliso Viejo that killed his former girlfriend and business partner, FBI officials say.Federal officials were searching the man's Long Beach home near El Paseo Street and Volk Avenue on Sunday. Neighbors reported seeing FBI and SWAT officials breaking down the home's front door.Further details on the arrest were not immediately released. A press conference is expected to be held on Monday.In May 2018, investigators said a blast from a packaged device killed 48-year-old Ildiko Krajnyak at her spa in Aliso Viejo . Authorities said it was unclear how the package was delivered to Krajnyak.A suspect or motive was not identified at the time, but neighbors said one man who is familiar with explosives is Beal, who is also a known rocket-building hobbyist."He used to make rockets about as big as I am. He would do it in the driveway by his garage. He'd go out to the desert and fire them off," neighbor Mushroom Montoya said.Neighbors also said Beal and Krajnyak dated and that he was an investor in her day spa. Pictures of the pair are on Beal's Facebook page, which shows them traveling around the world."If I were the police and I have an explosive issue - a bombing - and I come to this house and I find rocket fuel plus they were business partners, then all these things kind of enter into play in terms of it being suspicious," Montoya said.The last time neighbors saw Krajnyak was about a month before the explosion, and so they assumed the two ended their relationship.