ALISO VIEJO, Calif. (AP) — A deadly explosion that ripped through a Southern California day spa was a crime, authorities said Wednesday as they tried to figure out why someone would target a business that provided facials, waxing and wrinkle treatments.

Authorities declined to say if they believed the fatally injured spa owner was targeted, but one official briefed on the investigation told The Associated Press that the dead woman had been the intended recipient of an explosive package.

Remnants of an explosive device were found inside the badly damaged spa where the powerful explosion Tuesday afternoon shook the city of Aliso Viejo, about 50 miles (80.5 kilometers) south of Los Angeles, and tore a corner off the building housing medical offices. Two patrons were seriously injured.

"We do not believe this was an accident," said Paul Delacourt, special agent in charge of the FBI's field office in Los Angeles. "Although the damage was extensive, there are some components that we have located at the scene of the explosion that are inconsistent with what one might expect to find at this business."

Investigators were working to determine a motive and figure out exactly how the device got to the spa, Delacourt said. No arrests were made.

The blast is believed to have been caused by an explosive package sent to the spa, two officials told the AP. The spa owner was believed to be the target, one official said.

The officials were briefed on the investigation but not authorized to discuss the matter publicly and spoke to AP on condition of anonymity.

Formal identification of the body was continuing but authorities believe it was Ildiko Krajnyak (IL-di-koh KRY-nyak), a licensed cosmetologist, who owned the spa.

Krajnyak, 48, was originally from Hungary and had just visited there, according to her Facebook page, which showed photos from Budapest.

A voicemail at her business said the spa was closed through Monday and would reopen Tuesday, the day of the blast.

The two customers injured underwent surgery Wednesday and were expected to survive. A third victim was treated for smoke inhalation.

Search warrants were served at three locations, including Krajnyak's house in Trabuco Canyon.

A neighbor there who would only give her first name as Tiffany said Krajnyak lived in the house with her estranged husband and mother, whom she cared for. A son was attending college in Washington state.

Tiffany said the family still hadn't been notified Wednesday if Krajnyak was dead or alive.

The couple, although separated, continued to live under the same roof, the neighbor said. Court records show they had filed jointly for bankruptcy in 2014 and the case was dismissed and closed Monday.

Attorney Andrew Bisom, who represented Krajnyak and Ronilo Vestil during the Chapter 13 bankruptcy proceedings, said they were far along on their mandated payment plan but hadn't completed it.

Bisom did not know them well and said there was nothing that stood out about them or their case.

The two-story building where the explosion had blown siding off the walls and shattered windows was closed Wednesday as bomb technicians and investigators from the Orange County Sheriff's Department, the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives sifted through debris.

Pieces of the explosive device recovered were sent to the FBI's laboratory in Quantico, Virginia, to be analyzed, Delacourt said.

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Balsamo reported from Los Angeles. Associated Press journalists Amy Taxin in Santa Ana, Brian Melley, Christopher Weber and John Antczak in Los Angeles and researcher Rhonda Shafner in New York contributed to this report.

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