Huu Can Tran, 72, who was subsequently discovered dead in a white van, has been named by California authorities as the shooter who is suspected of killing 10 people in a ballroom dance studio close to Los Angeles.
He had a self-inflicted gunshot wound and was declared dead at the scene, LA County Sheriff Robert Luna said.
Celebrations for Lunar New Year had been under way in Monterey Park, known for its large Asian population.
Police do not yet know the motive.
Another 10 people were wounded in the shooting, and seven are still in hospital – some in a critical condition – the sheriff said at a news conference on Sunday afternoon in Monterey Park.
He added that the 10 people who died were still being identified, but they seemed to be in their 50s and 60s and some perhaps older.
Earlier, officials said five women and five men had been killed, all “probably” of Asian descent.
The mass shooting, one of the deadliest in California’s history, began at around 22:22 local time on Saturday (06:22 GMT on Sunday) at the popular Star Ballroom Dance Studio in Monterey Park, about seven miles (11km) east of central Los Angeles.
Police Chief Scott Wiese said that what his officers found was a “scene of carnage”, and that the first officers to get there were some of the youngest on his squad, having only just finished their training a few months ago.
“They came across a scene none of them have prepared for,” he said. “There were injured people inside and dead people inside. My young officers did their job.”
About 30 minutes later, the gunman arrived at another dance studio in the nearby town of Alhambra.
He entered the studio, but two people managed to wrestle the weapon off him – a semi-automatic assault pistol with an extended magazine – and he escaped.
Sheriff Luna said he believed the weapon was illegal in California, although added he needed to investigate that further.
He praised the “two community members, who I consider to be heroes. They saved lives, this could’ve been much worse,” the sheriff said, adding that he believes Tran intended to kill more people.
For hours on Sunday, authorities scoured the Los Angeles area in search of the gunman.
Just before 13:00 local time (21:00 GMT) – about 12 hours after the shooting – a SWAT team swarmed a white van in a carpark in Torrance, about 30 miles (48km) from the Monterey Park shooting scene.
Sheriff Luna said they heard a single shot from inside the van as they approached, and then found the suspect slumped over the steering wheel. Evidence including a handgun was recovered, and the man was identified as the gunman.
The sheriff said the gunman is believed to have acted alone, and there were no other suspects.
He said police “assume” the number plates on the van were stolen.
Monterey Park’s population is about 65% Asian American – it has been called America’s first “Chinese suburb”. It became the first mainland US city to have a majority of residents with Asian ancestry.
The dance studio where the deadly shooting happened was known locally as a popular venue, especially on Saturday nights.
One man who taught ballroom dancing there, Alex Satrain, told the Washington Post that the studio’s regulars were “like a family”.
With a community in mourning, the Monterey Park celebrations of Lunar New Year were cancelled. Businesses began removing the red lanterns and festive banners that had adorned the streets.
Source: BBC