A deadly explosion at a medical office building in Aliso Viejo is believed to have been an intentional act and is being investigated as a crime, authorities said Wednesday.
One woman was killed and three others were injured in the blast, which occurred about 1:10 p.m. in the first floor of the two-story building at 11 Mareblu, according to the Orange County Fire Authority.
The victim has been identified as 48-year-old Ildiko Krajnyak of Trabuco Canyon, and she is believed to have owned the day spa where the explosion went off, Orange County Undersheriff Don Barnes said at an early afternoon Wednesday conference.
Evidence at the scene suggested the material in the explosive was not consistent with items found at a day spa, according to Barnes.
"We do not believe at this time that it was an accident," he said. "At this time we ruled out the potential of this being an accident due to the condition of the victim.”
Due to the extent of her injuries, the body has not been positively identified by coroner's officials.
Krajnyak is survived by one son, a student at the University of Washington, according to a GoFundMe page.
Bomb technicians from multiple agencies are working diligently to determine the source of the blast, which may have come from some type of device. Evidence has been sent back to the FBI's headquarters in Quantico, Virginia, for analysis, according to Paul Delacourt, the assistant director in charge of the agency's Los Angeles Field Office.
"We've ruled out a gas main explosion and other potential theories," he said at the news conference. "At this point, our working theory is that this explosion was caused by a device."
The Los Angeles Times, citing two law enforcement sources, reported that investigators believed it may have been caused by a package. However, authorities were adamant that they could not confirm where the device came from and how it was delivered.
"We do not know how the device arrived at the location," Delacourt said.
They believe the victim was in close proximity to the explosion, while the three others who were injured were likely near her at the time.
Two of the wounded women suffered "severe" injuries and were taken to local hospitals, where they underwent surgery. Both are expected to survive, Barnes said.
Both of those victims were customers of Krajnyak's, according to the Times.
A third victim was treated at the scene for smoke inhalation.
It was unclear whether Krajnyak had been targeted, Barnes said. A motive remains unknown, though the incident is being investigated as a crime, with the sheriff's Homicide Detail serving as the lead investigators.
Federal officials from the FBI, Bureau of Alcohol, Tobacco, Firearms and Explosives and the Department of Homeland Security have been called out to assist local authorities.
The incident is not believed to be terrorism, and there is no information indicating that there are any additional threats to the community.
"We don’t rule out anything, but at this point there is nothing that leads us to believe that there are [more targets]," Barnes said. He cautioned: "Until we can prove otherwise, everything is being investigated.”
The undersheriff stated that three search warrants have been served in connection with the investigation: in Aliso Viejo, Trabuco Canyon and Long Beach. He did not provide any additional details, however, saying only that investigators were pursuing any leads in the case.
However, law enforcement sources told the Times that the warrants involved Krajnyak's business, her home and the Long Beach residence of a business associate, where investigators hoped to turn up information on her romantic, personal and financial relationships.
A neighbor at the home where the Long Beach warrant was served said the man who lived there, Steve Beal, was a co-owned in the day spa and had also been in a romantic relationship with Krajnyak until they broke up about a month ago. The person said he believed Beal was being scrutinized because he likes to build rockets and set them off in the desert.
No arrests have been made, Barnes emphasized. There was no information about any possible suspect or suspects.
On Wednesday morning, FBI agents could be seen outside Krajnyak's two-story home in the Coto De Caza community, video from the scene showed. The woman had lived in the community for about 15 years and shared the home with her husband, her son and her mother, according to neighbors.
Residents said there was a lot of action overnight at the property, with 50 or more law enforcement officers descending on the quiet neighborhood and they began to investigate. The area has been under surveillance since a short time after the explosion, according to neighbors.
Authorities provided no additional information about the search.
The victim's son Keanu told KTLA in an interview before Krajnyak had was identified as the victim that the family had not heard from him since before the explosion. He expressed concern for other relatives -- in particular his grandmother -- who were still trying to process everything.
"The ... concern I would have is that my grandmother lives at my house, and she doesn't speak English or understand it," Keanu said in a phone interview. He added that his grandmother was in poor health and suffered a heart attack the last time she was stressed.
Neighbors described Krajnyak, a licensed aesthetician, as a hard-working woman who traveled a lot and, in fact, had just recently returned from a trip to Hungary, her native country.
She owned the day spa -- called Magyar Kozemetika -- where the fatal explosion took place, according to business owners in the building.
Damage at the scene was described as "extensive" by an FBI official. Throughout the medical office building, some windows and walls were blown out, while ceilings and roofs partially collapsed or caved in; debris landed in a nearby parking lot as well as the street, video showed.
While the building has since been deemed safe, all businesses on Mareblu were closed Wednesday amid the ongoing investigation, according to a tweet from the city of Aliso Viejo. The street has also been closed off to through traffic.
It was not immediately known how long the closures would last.
Anyone with information about the case is urged to call the FBI's tip line at 1-800-CALL-FBI.
KTLA's Salina Nasir and Erika Martin contributed to this story.