LOS ANGELES (AP) — In the course of 48 hours, two gunmen went on shooting rampages at both ends of California that left 18 dead and 10 wounded.

The unrelated massacres at a dance hall in a Los Angeles suburb on Saturday night and a pair of mushroom farms south of San Francisco on Monday have dealt a blow to the state, which has some of the nation's toughest firearm laws and lowest rates of gun deaths.

As communities mourned the dead, some Democratic politicians repeated calls for tougher gun controls on the federal level.

Here are some things to know about the shootings:

WHAT HAPPENED IN MONTEREY PARK?

Hours after the city of Monterey Park held a large Lunar New Year celebration, a gunman stormed the Star Dance Ballroom and shot 20 people, killing 11. Police arrived within minutes to a scene of chaos and carnage as people ran from the club in fear — and others lay sprawled on the dance floor or slumped in chairs at tables. The victims were older Asian Americans, mostly in their 60s and 70s.

The shooter, Huu Can Tran, 72, then drove to Lai Lai Ballroom in nearby Alhambra where police said he tried to carry out a similar attack some 20 minutes later. He was met inside the door by Brandon Tsay, 26, an employee whose father and sister own the club, who made a split-second decision to lunge for the weapon. He disarmed Tran after a brief struggle.

Tran fled in a white van, where he was found dead Sunday morning from a self-inflicted gunshot.

The rampage cast a pall over the typically joyful new year celebrations, and renewed fears in Asian American communities about increased hatred and violence directed at them.

WHAT HAPPENED IN HALF MOON BAY?

A farmworker, who told a television reporter Thursday that his complaints of being bullied and working long hours were ignored, shot five co-workers, killing four, at a mushroom farm Monday in Half Moon Bay, authorities said. He then drove to a nearby farm where he used to work and killed three more people.

Chunli Zhao, 66, admitted to KNTV-TV that he carried out the shootings, and said he struggled with mental illness and was not in his right mind at the time. He later surrendered to police, and was taken into custody and held without bail.

Five of the victims were of Asian descent and three were Hispanic. All but two were in their 60s and 70s.

WHAT'S NEXT?

Zhao faces arraignment Feb. 16 in San Mateo County Superior Court on seven counts of murder and one attempted murder charge. He could face the death penalty if convicted.

Detectives are still investigating the shootings.

No criminal case is expected in Los Angeles County because Tran is dead and authorities said he acted alone.

However, the investigation continues into what drove Tran to kill. So far, the Los Angeles sheriff said they haven't determined a motive.

A longtime friend told The Associated Press that Tran frequented both dance halls he targeted and complained about the way he was treated there. The man, who asked not to be named, said Tran fancied himself a dance instructor and would offer women free lessons so he'd have a partner, and he felt the teachers looked down on him.

But Sheriff Robert Luna said there was no evidence Tran knew any of the people he killed and he hadn't been to the ballroom in five years.

Tran's criminal record only included an arrest from 1990 for illegal possession of a gun.

HOW DID THE SHOOTERS GET FIREARMS?

Zhao, a Chinese immigrant with a green card, told KNTV he bought his gun in 2021 without any difficulty.

Officials have said he purchased the semiautomatic handgun legally but provided no other details.

Tran, who was originally from Vietnam, bought the submachine gun-style semiautomatic pistol that he used in Monterey Park in 1999, the sheriff said. The gun and the high-capacity magazine are illegal in California, and it wasn't registered in the state.

He fired at least 42 bullets from the gun variant of the MAC-10 semiautomatic machine pistol, taking time to reload his 30-round magazine.

The semiautomatic handgun Tran used to take his own life was registered, as was a bolt-action rifle found at his home in Hemet, about 70 miles (112 kilometers) from Monterey Park, Luna said.

WHY DID IT TAKE SO LONG FOR POLICE TO NOTIFY THE PUBLIC?

Authorities in Southern California have defended their decision not to notify the public for more than five hours that a killer was on the loose after the dance hall shooting and subsequent attempted attack.

Monterey Park Chief Scott Wiese said police in the region were alerted and it didn’t make sense to warn residents at night in the predominantly Asian American city even though a potentially armed suspect was at large.

“I’m not going to send my officers door to door waking people up and telling them that we’re looking for a male Asian in Monterey Park,” Wiese told The Associated Press. “It’s not going to do us any good.”

Luna, who is leading the investigation, said his department’s decision on when to release information was “strategic” but promised to review the timeline.

Experts said authorities should have alerted the public sooner.

WHICH LEADERS HAVE SHOWN SYMPATHY AND SUPPORT?

Pope Francis and President Joe Biden have sent condolences, and messages of support.

Vice President Kamala Harris added a bouquet of flowers to a growing memorial outside the locked gate of the Monterey Park studio on Wednesday and — like many Democrats — called on Congress to enact tighter gun laws.

“Tragically we keep saying the same things,” Harris said. “Can they do something? Yes. Should they do something? Yes. Will they do something? That is where we all must speak up.”

Biden urged lawmakers to support a ban on assault weapons introduced by U.S. Sen. Dianne Feinstein.

WHO IS THE HERO IN LOS ANGELES?

Tsay has been widely praised for his heroic actions that were credited for saving countless lives.

President Joe Biden thanked him by phone Thursday for “taking such incredible action in the face of danger.”

“You are America,” Biden said in a video posted on Twitter. “You are who we are. America has never backed down. We’ve always stepped up because of people like you.”

Tsay, 26, said he was comforted by Biden’s words.

Police in Alhambra planned to award him a courage medal on Sunday at the city's Lunar New Year Festival, the Chamber of Commerce announced Thursday.

While Tsay said he was proud of what he did, he told reporters outside his home Monday that he didn’t want to discuss his actions but, rather, keep the focus on the people who lost their lives, and those who were wounded.