ORANGE, Calif. — Four people, including a child, were killed in a shooting at an office building in Southern California on Wednesday, the authorities said, bringing a deadly close to a month consumed by a series of high-profile cases of gun violence.
The gunfire occurred around 5:30 p.m. in Orange, Calif., about 30 miles southeast of Los Angeles, according to the police there, who said a fifth victim, a woman, was hospitalized in critical condition with a gunshot wound.
A suspect was also hospitalized in critical condition with a gunshot wound, the authorities said. They added that it was not yet known if the wound was self-inflicted.
It was not immediately clear what led to the shooting, and additional details about the victims and the suspect were not available from the authorities. They said a firearm had been recovered at the scene, which covered two floors and a courtyard area of the building.
Lt. Jennifer Amat, a spokeswoman for the Orange Police Department, said at a news conference on Wednesday night that officers had responded to the area of 202 West Lincoln Avenue near Glassell Street after reports of shots fired.
When officers arrived, the shots were still being fired and the police found several victims, said the police.
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. The two men, along with residents who were at the scene on Wednesday night, said they believed the shooting had unfolded at a real estate office on the second floor. The windows of the office appeared to have been shot out.
Mr. Gomez said the woman who ran the office sold mobile homes and 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 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 Wednesday’s shooting was the worst homicide in Orange 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.”
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.
Louis Keene reported from Orange, Calif., Neil Vigdor from Greenwich, Conn., and Jacey Fortin from New York. Manny Fernandez contributed reporting from Los Angeles.