An explosion in May rocked a neighborhood in Orange County, Calif., and killed a spa owner. (Orange County Register/Orange County Register)

Only two customers were inside the Magyar Kozmetika day spa on the afternoon that tragedy shut down the Southern California business for good.

A mother and daughter had finished their treatments about 1 p.m. on May 15 when they approached the front desk at the spa in Aliso Viejo, Calif., to pay, a federal affidavit would later document. The spa’s co-owner, Ildiko Krajnyak, 48, was sorting through the mail. Four cardboard boxes were laid out on the floor. As the customers watched, Krajnyak hefted one onto the desk and ripped open the flaps.

Flames and smoke swallowed up the spa. The blast shattered the windows, shot glass and human flesh out onto the parking lot and palm trees outside, and set car alarms screaming across the Orange County neighborhood.

“Then everyone started running out of buildings everywhere with looks on their faces of just horror,” a witness later recounted to NBC San Diego. “I saw two women come out full of blood, hair singed, just glass stuck to the hair, glass stuck to their bodies. Their skin was burned and peeled back, and they were just in shock.”

The mother and daughter — presumably the figures spotted leaving the blast-crushed building — remarkably survived the explosion but required hospital treatment for burns and lacerations. Krajnyak, however, was killed. “We do not believe at this time that this was an accident,” Donald Barnes, then Orange County undersheriff, told reporters at a news conference at the time.

Following a nine-month investigation, authorities announced that Stephen Beal, 59 — Krajnyak’s ex-boyfriend and business partner at the spa — was arrested Sunday in connection with the explosion. U.S. Attorney Nicola T. Hanna said during a news conference Monday that Beal, who authorities believe was targeting Krajnyak, has been federally charged with malicious destruction of a building resulting in death, which carries a potential sentence of life in prison.

It’s unclear whether Beal has an attorney in the case.

“This was a horrific, intentional attack that killed an innocent woman and severely injured two others,” Hanna told reporters. “Those two surviving victims will have to live with the physical and emotional scars of this attack for the rest of their lives. We will do everything possible to secure justice for those victims and to bring the perpetrator to account.”

Authorities said that during the exhaustive, months-long investigation, they processed 1,000 pieces of evidence from the scene and subsequent searches, including boxes, wire and a partially destroyed battery that led them to Beal. Authorities did not speak about a possible motive but said that leading up to the explosion, Krajnyak had admitted to being in a relationship with another man — and she and Beal split up — and that Beal admitted to feeling “betrayed.”

Beal had been a suspect in the bombing since the early days of the investigation, leading to his arrest in May after a search turned up 130 pounds of explosives and chemical precursors in his garage, as well as two improvised explosive devices.

At the time, Beal claimed the items were tied to his model rocket hobby. A federal criminal charge of possessing an unregistered destructive device was later dropped, and he was released from custody.

Beal and Krajnyak’s relationship started as a jet-setting romance that spun into a business arrangement.

Beal was a part-time actor who had been building his own fireworks and model rockets since the late 1990s, according to a federal arrest affidavit filed last year. The Los Angeles Times reported last year that Beal would fire off his homemade rockets near Edwards Air Force Base. In an interview with authorities after the explosion, Beal said that he had lost interest in rockets in 2004, after one of his creations attained Mach 2 speed.

In the same interview, Beal told investigators that he had met Krajnyak on an online dating site and that the two began seeing each other in June 2016. Krajnyak, a skin-care expert, had opened the spa in 2006. The couple crisscrossed the world, including vacations to Canada, Cuba and Portugal, according to the Times.

The couple eventually went into business together. However, by March 2018, the relationship “began to cool,” Beal later told investigators, “due to disputes over the exclusivity of the relationship and financial issues,” according to the federal affidavit. They split up but continued to act as business partners. Beal paid the $1,500 monthly rent on the spa’s space and half the operating costs.

“Some months he would have to loan Krajnyak money to cover all of the costs,” the affidavit states. “Other months, she made enough to cover the costs.”

After the explosion, Beal contacted authorities after seeing the destruction on the news. He consented to a search of his property, according to the affidavit. In a pool house and garage structure on his property, authorities discovered cardboard tubes, batteries, 130 pounds of explosives and other chemicals, black powder, as well as two handguns and a shotgun.

Beal told investigators that the devices were related to his rocket hobby, as well as a device he designed for his neighbor’s gopher problem. But the federal affidavit noted that the evidence collected from Beal’s property was “not consistent with that of a model rocket.” Nevertheless, two weeks after he was charged with possessing an unregistered destructive device, the charge was dropped.

“Further examination by the Federal Bureau of Investigation raises questions as to whether the devices meet the statutory definition for a ‘destructive device,’ ” the U.S. attorney’s office stated in court documents, according to the Times.

In a strange twist, Beal’s arrest in the explosion has reportedly drawn investigators to take a look at his wife’s death in 2008. According to the Long Beach Press-Telegram, Christine Beal died in Long Beach, Calif., after a large piece of furniture fell on her as she and Beal were trying to move it.

The coroner, however, said the cause of death was “undetermined,” and noted “chronic lead intoxication” as well as “pancreatitis, electrolyte imbalance and other undetermined factors” in the woman.

On Sunday, Long Beach authorities told the Press-Telegram that they were reassessing her death. The Times reported that Beal attempted to claim a $21,225 life insurance payout from his wife’s death but that the claim was denied at least once. It is unclear whether he ever received the money.

“The cause of death was undetermined so it was a coroner’s case,” police spokeswoman Nancy Pratt told the paper. “Right now, detectives are taking a look at it.”

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