ORANGE, Calif. — A gunman opened fire at a Southern California real estate office on Wednesday, killing four people, including a 9-year-old boy who the authorities said appeared to have died in his mother’s arms as she tried to shield him from the gunfire.
The shooting was likely related to a “business and personal relationship which existed between the suspect and all of the victims,” said Lt. Jennifer Amat, a spokeswoman for the Orange Police Department, at a news conference on Thursday morning.
“This appears to be an isolated incident, and we believe everyone knew each other,” Lieutenant Amat said.
The boy appeared to have died in his mother’s arms as she attempted to save him during the shooting, the Orange County district attorney, Todd Spitzer, said, before cautioning that a formal identification of the boy and the woman had not yet been made. The woman was also wounded in the shooting and remained in the hospital on Thursday, having undergone emergency treatment.
The suspect, identified as Aminadab Gaxiola Gonzalez, 44, of Fullerton, was also hospitalized in critical condition with a gunshot wound, the authorities said.
The victims, who also included a man and two women, were attacked at the offices of Unified Homes, which is a real estate and mobile home dealer, according to the business’s website. Additional details about the victims were not yet available from police officials.
At the scene, which covered two floors and a courtyard area of the building, officials recovered several items including a semiautomatic handgun and a backpack containing pepper spray, handcuffs and ammunition, Lieutenant Amat said, which officials believe belonged to the suspect.
Mr. Gonzalez, the suspect, locked the gates to the complex with bicycle cable locks, and officers had to force their way into the scene, officials said.
In March, two mass shootings — one in Atlanta and the other in Boulder, Colo. — occurred within one week. In Atlanta on March 16, a gunman shot and killed eight people, six of them women of Asian descent, at three spas. On March 22, a man stormed a grocery store in Boulder and killed 10 people.
The shooting in Orange set people on edge both near and far from the scene, in part because until the shooting in Atlanta, it had been a year since there had been a large-scale shooting in a public place in the United States, according to the Violence Project.
But researchers say that the kind of violence that unfolded at the office building never went away in the pandemic — it simply went out of view. Data from the Violence Project shows that in 2020 there were more than 600 shootings in which four or more people were shot by one person, compared with 417 in 2019.
The gunfire began around 5:30 p.m. Wednesday in Orange, about 30 miles southeast of Los Angeles, according to the authorities.
Two police officers discharged their weapons at the scene on Wednesday, and both officers were wearing body cameras, said Kimberly Edds, a spokeswoman for the Orange County District Attorney’s Office.
It was unclear as of Thursday whether the suspect’s injuries were self-inflicted or were caused by officers discharging their weapons, Ms. Edds said, adding that charges against the suspect would likely be filed sometime on Thursday.
Emma Soto, 26, who lives in an apartment near the building, was doing laundry when she said she heard seven to 10 gunshots.
“It just sounded like a popping sound,” she said. “It didn’t really sound like how you would imagine it, like in the movies. We’re hearing of all these shootings going on, so I just thought, ‘Another shooting.’ But we never imagined it would be that close to us.”
Almost immediately after hearing the gunfire, Ms. Soto said, several police vehicles pulled up. She watched as officers emerged from the vehicles with their weapons drawn. The officers ran toward the building, she said.
The neighborhood is typically quiet and peaceful, and it is largely Hispanic, said Ms. Soto, a manager at a nearby big-box store. “It’s scary,” she said of the shooting.
Hope Orozco, 27, was with her 3-year-old son at a neighbor’s house when she said she heard the gunfire. She said her son likes to watch her neighbor’s children play Call of Duty, the popular combat video game. At first, she said, she mistook the commotion outside for the sounds of the game.
“I was like, ‘Wait a minute, is this from the TV?’” Ms. Orozco said. She realized it was real after noticing all the players were connected to headsets.
Hector Gomez and Edgar Gonzalez work at a roofing business located on the first floor of the building where the shooting occurred.
Mr. Gomez said the woman who ran the real estate office would often bring her son with her to the building.
“He’s a cute little boy,” Mr. Gomez said.
The two men said they were convinced the woman and her son were among the victims. The woman’s S.U.V. was still in the parking lot, they said, as the police conducted their investigation late into the evening.
Mr. Gomez and Mr. Gonzalez usually leave the office around 5:30 p.m., when the shooting happened. On Wednesday, they left early. They came back after hearing about the shooting from their boss.
“It could have been us,” Mr. Gomez said. “I don’t want to say this, but it probably would have been us. Because we’re always the last ones here.”
Orange is a city of 139,000 less than six miles from Disneyland. Late Wednesday evening, about a dozen police and fire vehicles blocked the wide Lincoln Avenue. The squat commercial building where the shooting took place is mostly surrounded by homes and apartment buildings.
The beige, low-rise building in Orange houses several businesses, including a property management company, insurance agency and a consulting firm.
The owner of an auto repair shop next door, who asked not to be named, said he heard around four gunshots. A few minutes later, he said, the police surrounded the building.
He heard at least 10 more gunshots after that, he said, though he still did not know exactly what had happened.
“It was weird to have something like that happening next door,” he said. “We’d never heard anything like that before.”
Lieutenant Amat called the shooting “a tragedy for the victims, their families, our community and our police department.” She said that the city of Orange had not seen “an incident like this” since a rampage in 1997 at a Caltrans maintenance yard, in which a gunman killed four people and was later killed by the police in a shootout.
Gov. Gavin Newsom of California said on Twitter that he was jolted by the shooting.
“Horrifying and heartbreaking,” he said. “Our hearts are with the families impacted by this terrible tragedy tonight.”
Representative Katie Porter, a Democrat whose district includes part of Orange, expressed her sorrow on Twitter over the shooting.
“I’m deeply saddened by reports of a mass shooting in Orange County, and I’m continuing to keep victims and their loved ones in my thoughts as we continue to learn more,” she said. “My team and I will continue to monitor the situation closely.”
Louis Keene reported from Orange, Calif., and Giulia McDonnell Nieto del Rio from New York. Reporting was contributed by Neil Vigdor from Greenwich, Conn., Jacey Fortin from New York, and Manny Fernandez from Los Angeles.