Here are the top 10 points from this big story
The 72-year-old yesterday opened fire at a Chinese Lunar New Year party at Monterey Park in California's Los Angeles. Police tracked him down to a van and surrounded it. As the officers approached the vehicle, they heard a gunshot.
"The suspect sustained a self-inflicted gunshot wound and was pronounced dead at the scene," Los Angeles County Sheriff Robert Luna said.
The sheriff confirmed that there are no other suspects in the mass shooting incident, and added that the motive for the attack was not yet known. "The investigation is still ongoing," he said.
Officials have said detectives were reviewing surveillance video and did not yet know whether the suspect was targeting a particular group.
"We don't know if this is specifically a hate crime defined by law but who walks into a dance hall and guns down 20 people?", sheriff Luna earlier said.
US President Joe Biden has ordered all US flags at public buildings to be flown at half-staff to honour the victims of the mass shooting, the White House said in a statement.
Tens of thousands of people had gathered for the two-day Lunar New Year festival, one of the largest in southern California. The second day of the festival was cancelled after the attack.
The shooting, the deadliest in the US since a shooter in Texas killed 21 people at an elementary school in May, has yet again brought under the spotlight rising gun violence in the country and easy access to firearms.
The last year saw as many as 647 incidents of mass shooting, with at least four people shot or killed by a shooter, according to the Gun Violence Archive website.
More than 44,000 people died from gunshot wounds in 2022 across the US, more than half of which were suicides.
4 Killed In Mass Shooting At Birthday Pool Party In US, Suspect Kills Self 6 Years After US Mass Shooting, Crew Begins Demolition Of School Building 1 Dead, 24 Injured In Mass Shooting In US, Probe Launched: Report 25,000 Aspirants For Airport Jobs Paying Rs 22,000: A Mumbai Stampede Scare 4 Top Leaders Quit Ajit Pawar's Party In Major Setback After Poll Drubbing Trump's Running Mate Calls UK "Truly Islamist State With Nuclear Weapons" Why Donald Trump Picked JD Vance As His Vice President Candidate Rs 1.98 Crore Relief In Mercedes Hit-And-Run, Car Was Driven By Minor "By Hook Or Crook, He's Behind Bars": Arvind Kejriwal Lawyer In High Court Track Latest News Live on NDTV.com and get news updates from India and around the world.