LOS ANGELES — In the more than two decades since they left China and landed in the vast Southern California suburbs, Jeff and Nancy Liu did almost everything together. That’s where they were on Saturday night as a gunman opened fire on the ballroom dance floor where they were celebrating the new year and enjoying one of their favorite pastimes.

On Monday, with her 62-year-old father recovering from gunshot wounds and the whereabouts of her 63-year-old mother uncertain, Juno Blees, the Lius’ daughter, finally got the news she had been dreading. Her mother had been one of at least 11 people killed when what had been a dreamy refuge for hundreds of immigrants exploded into yet another spasm of American mass violence.

It was not unusual for people like the Lius to spend large parts of their days and weeks at the Star Ballroom Dance Studio in Monterey Park, Calif., where the shooting happened, taking private and group lessons, singing karaoke in the back room and socializing in the evenings, said David DuVal, 53, who has taught at the studio for a decade..

“Before the pandemic they had parties every night, it’s kind of like you go get your exercise, they would play music and you can hang out and dance,” Mr. DuVal said. Although many people would show up as dance couples, there were also often students who needed a partner and who would hire one of their instructors or another dancer for the night. It was common for more than 100 people to show up, Mr. DuVal said.

Sometimes evenings would be formal affairs where students would perform in showcases, displaying what they had learned in class. Instructors preparing for competition would use the willing audience for a dress rehearsal.

At one point, there was a competition between the owners of Star Ballroom and another nearby dance hall, Lai Lai Ballroom & Studio, over party attendance and instructors, said Mr. DuVal. But that didn’t stop students and teachers from frequenting both places, nor did it break up friendships in the community.

Like Southern California, the scene is diverse: Regulars said classes were typically raucous with conversations and music in English, Cantonese and Mandarin, as dancers born in the Philippines, China, Taiwan and Hong Kong bonded with instructors, many of whom were born in Europe.

“In Los Angeles, but maybe in this country, it would be the Asian American communities that have kept ballroom dancing alive,” Kristina Hayes, a Los Angeles dance instructor, said.

Some enter competitions, instructors say, but most are there simply to learn the rumba, cha-cha, tango, waltz, salsa or fox trot. For many, the studios offer an opportunity to learn an elite skill that may have intrigued them in their youth, but for which they could never find the time or money.

Laura Nix, a Los Angeles-based director, spent seven years immersed in the culture at Lai Lai while filming an Oscar-nominated short documentary on a local Chinese Vietnamese couple, one an accountant, the other an engineer, who rediscovered each other and themselves through ballroom dancing.

“When you watch people dance there and at places like Star Dance, you see the purest expression of a tight-knit community, and people embracing life — that’s one reason why the violence directed at their patrons is so devastating,” she said.

The Los Angeles County coroner’s office has identified four of the victims of the shooting. The coroner’s office is waiting until relatives have been notified to identify the rest.

Six women were killed, including My Nhan, 65, Lilan Li, 63, and Xiujuan Yu, who at 57 is the youngest . Two other women in their 60s also died. Only one of the male victims was identified, Valentino Alvero, 68. Three still-unidentified men who were killed were in their 70s and one was in his 60s.

Investigators are still sifting through the aftermath of the deadliest mass shooting since last May, when 19 children and two teachers were killed in Uvalde, Texas. But as the victims have been identified, they have brought into relief at least one piece of the picture.

Men and women in late middle age or older, nearly all were denizens of the flourishing ballroom dance culture that has arisen in Southern California, revived by immigrants who have found a fresh passion in the competitive art form.

The family of Ms. Nhan, in a statement, remembered her “warm smile,” and her support (“Mymy was our biggest cheerleader”), for example, but also her passion for ballroom dancing.

Credit…Fonda Quan, via Associated Press

Also dead, according to his family, was Ming Wei Ma, the studio’s older manager and popular co-owner, whose friends and family similarly associated him with the ballroom.

Heather Smith, a former U.S. ballroom dance champion who coached dancers twice a month at Star Ballroom Dance Studio, recalled him as a beloved figure in the area’s passionate community of dancers. When she taught group classes, she said, Mr. Ma would join in and take pictures, proud of the diversity of the studio’s instructors.

“Every time I went there,” she said, “Mr. Ma would hug me and say, ‘Champion in the house!’”

Star Ballroom and Lai Lai, where the gunman was disarmed by the owner’s grandson before fleeing, are less than three miles apart, with rosters of longstanding, first-generation Asian American students.

Peter Phung, 58, and Tiffany Phung, 55, a married couple live close to the Star Dance Studio and have known Mr. Ma for years. On Monday, they stood outside the studio to pay their respects to the victims of the shooting. Mrs. Phung said she had been texting with a friend who she found out was pronounced dead on Sunday night.

They described Mr. Ma as a kind of community impresario, recruiting dancers to the studio, hosting karaoke nights and staging performances.

Mrs. Phung danced in the revues, some of which were themed for holidays, while Mr. Phung sang Chinese love songs, like “We Are Different.”

Mrs. Phung remembered that Mr. Ma spotted her as she headed to modeling classes nearby.

“He’d say, ‘Beautiful girl, why don’t you take dance classes?’” Ms. Phung recalled with a laugh. A couple of years ago, she obliged. Recently, she started taking Latin dance classes on Friday nights with a female instructor, “because I don’t want my husband jealous,” she said.

Elizabeth Yang, 40, said the club has become a “generational” experience. “My mom used to take dance lessons there when she was younger,” she said. “I started dancing there last year, and then I brought my daughter.”

She added: “I’m planning on bringing my daughter back. I’m not going to stay away.”

Jill Cowan, Edgar Sandoval and David W. Chen contributed reporting. Susan C. Beachy contributed research.