MONTEREY PARK, Calif. (AP) — The 72-year-old gunman who sprayed bullets into a Southern California ballroom dance hall, killing 11 people, had no known connection with the victims and investigators were still trying to determine a motive for the massacre, the Los Angeles County sheriff said.

Before the shooting Saturday night, Huu Can Tran parked a motorcycle just a block away from the ballroom in Monterey Park, which investigators believe he had planned to use as a backup getaway vehicle, Los Angeles County Sheriff Robert Luna said during a news conference Wednesday hours after police seized the motorcycle.

Tran opened fire on a mostly elderly crowd of dancers at the Star Ballroom Dance Studio, killing 11 people and wounding nine, police said.

The carnage, during what should have been joyful Lunar New Year celebrations, sent ripples of fear through Asian American communities already dealing with increased hatred and violence directed at them.

Some reports had said Tran frequented the dance hall and fancied himself as an instructor, but Luna said he hadn’t been there in at least five years and did not appear to target the victims specifically.

“We have not been able to establish a connection between the suspect and any of the victims thus far,” Luna said.

Luna said it wasn’t clear how long Tran had been planning the attack in the city about eight miles from downtown Los Angeles or what prompted him to spray at least 42 bullets, taking time to reload his weapon, a variant of the MAC-10 semiautomatic machine pistol with a 30-round magazine.

Tran’s motive continued to elude detectives days after the tragedy as they searched piles of items and paperwork seized from Tran’s home and a van he used to flee, the sheriff said.

“It doesn’t make sense,” Luna said. “It really doesn’t.”

About 20 minutes after the carnage in Monterey Park, Tran entered another dance hall about 3.5 miles away in Alhambra, where an employee confronted and disarmed him during a brief struggle. Tran later shot himself in the van where his body was found Sunday morning.

Tran, who was originally from Vietnam, bought the machine pistol in Monterey Park in 1999, but it was not registered in California, the sheriff said. The gun and the high-capacity magazine are illegal in California.

Luna said Tran used a registered semiautomatic handgun when he died by suicide, and a registered bolt-action rifle was found at his home in Hemet, about 70 miles from Monterey Park. His only known criminal history was a 1990 arrest for unlawful possession of a firearm, but there is no indication of whether he was convicted.

Monterey Park Police Chief Scott Wiese on Wednesday defended his decision not to warn the public for hours that a killer was on the loose, saying he did not have enough information at the time to effectively alert residents.

Wiese said police in the region were alerted but it didn’t make sense to send out a warning at night to residents in the predominantly Asian American city, even after learning the suspect may have targeted a nearby dance club after the massacre.

“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.”

The shooting at 10:22 p.m. Saturday occurred just an hour or so after tens of thousands of people attended Lunar New Year festivities in the city. The public was not notified of the mass shooting for five hours, raising questions about why an alert wasn’t sent to people in the area.

Wiese, who was sworn in as chief two days before the shooting, said police were piecing together information from some 40 witnesses, including many who didn’t speak English, and didn’t want to broadcast incorrect information. He said notifying other local, state and federal agencies gave them the ability to get the word out.

Less than 48 hours later, a gunman in Northern California shot eight fellow farmworkers, killing seven, at mushroom farms in Half Moon Bay. The shooter was of Chinese descent and most of the victims were Asian.

Outside the locked gates of in Monterey Park’s Star Dance Studio, a memorial grew higher Wednesday with mounds of bouquets and balloons. Hundreds of people carrying flowers, candles and incense showed up for a vigil.

Marlene Xu gathered with fellow dancers by a row of flower-framed photos of the victims. Xu said she danced at the studio four times a week and spent an entire day and night in tears after the violence.

“It’s hard for us because it’s a part of my life,” she said. “It’s like a part of your life is gone.”

Vice President Kamala Harris visited the memorial Wednesday, adding her own bouquet, before heading to a senior center to talk to relatives of the victims. She paused in front of each of the large, rose-framed placards that contained photos or names of the victims at the memorial.

Speaking briefly to reporters, Harris relayed sentiments on behalf of President Joe Biden and called for Congress to enact stricter gun control 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.”

Pope Francis was among those offering condolences, saying in a message to the Los Angeles archbishop that he “implores the divine gifts of healing and consolation upon the injured and bereaved.”

Wiese said he’s seen a lot during his three-decade career, but some of the first officers on the scene were rookies who had never faced such carnage and the trauma will be hard to forget.

Paramedics were loading the wounded into ambulances and treating others inside when the chief arrived. There were bodies every 10 feet: some slumped over tables, others sprawled on the dance floor.

“It’s hard to put words to it,” he said. “It takes your breath away when you see it. And it kind of burns the image into your brain.”