MONTEREY PARK, Calif. (NewsNation) — The Monterey Park shooting death toll increased to 11 Monday after one of the four people being treated at the LA County-USC Medical Center died of gunshot wounds, the Los Angeles County Department of Health Services said.

The suspect, 72-year-old Huu Can Tran, was found Sunday dead of a self-inflicted gunshot wound in a van in which authorities say he fled after people thwarted his attempt at a second shooting Saturday night. No other suspects were at large, Los Angeles County Sheriff Robert Luna said.

However, despite a three-minute police response to the scene, experts have thrown a spotlight on the nation’s flawed, patchwork system for warnings of mass shooters at large after it took police five hours to alert the public that the California dance hall killer was still on the run.

Police said the 72-year-old entered the Star Ballroom Dance Studio in Monterey Park and opened fire, killing five men and five women. He also injured at least nine others, with multiple still in the hospital Monday.

The Los Angeles County Dept. of Medical Examiner-Coroner has identified four of the victims as 65-year-old My Nhan; 63-year-old Lilan Li; 57-year-old Xiujuan Yu; and 68-year-old Valentino Alvero. The three other women have not been identified, but one is in her 70s and two are in their 60s. The four other men have not yet been identified as well, but three were in their 70s and one was in his 60s.

Even after the 72-year-old shooter brought a submachine gun-style weapon into another nearby dance hall about a half-hour after the first attack — a potential attack thwarted by a hero who grabbed the weapon and chased the man away — it would be hours more before police held a news conference to announce the suspect was still at large.

Experts say the weekend shooting highlights the lack of national standards for notifying the public, and the need for an aggressive alert system — similar to Amber alerts — that would immediately set off alarms on cellphones in surrounding areas and post warnings on highway signs.

“Five hours is kind of ridiculous,” said Chris Grollnek, an expert on active-shooter tactics and a retired police officer and SWAT team member. “This is going to be a really good case study. Why five hours?”

Los Angeles County Sheriff Robert Luna on Monday said his department was “strategic” in its decision to release information but that he would review what happened.

“When we started putting out public information, the priority was to get this person into custody,” Luna said. “Ultimately, it worked. We will go back and look at it as we always do. Nobody is as critical as ourselves as to what worked and specifically what didn’t work, and evaluate that, and see what the wait was in determining what the public risk was at that time.”

A timeline of events shows police were silent for hours, not only about a shooter being on the loose but about the fact that a shooting had taken place at all, with information trickling from police scanners and sources rather than official channels.

Monterey Park police said it took several minutes for officers — several of whom were rookies on the force — to assess the chaotic scene and look for the gunman, who had already fled.

About 20 minutes after the first shooting, at 10:44, the gunman marched into the Lai Lai Ballroom about 3 miles away in Alhambra. He was confronted in the lobby by 26-year-old Brandon Tsay.

It wasn’t until more than an hour later at 11:53 p.m. that word came that the shooter was still at large, and not from an official source, but from a media outlet monitoring police chatter on a scanner.

“We have the technology,” said former FBI agent Gregory Shaffer, now head of a Dallas-based risk management and tactical training firm. “It’s just not being utilized.”

A House bill last year would have established an Active Shooter Alert Network to replace the messy patchwork of alert systems used by thousands of towns and cities that are plagued by messaging delays and low enrollment. It died in the Senate, but one of its sponsors, U.S. Rep. Mike Thompson, a California Democrat, said late Monday he intends to re-introduce the legislation.

Monterey Park Mayor Henry Lo spoke with NewsNation on Monday morning, saying they are still trying to determine the motivation behind the attack. He said there has been some speculation about why he targeted the ballroom. 

“I understand that he met his ex-wife here 20 years ago, and he was a frequent attendee at the dance hall. But unfortunately, no, we still don’t fully know the motivation for him to do what he did during the Lunar New Year’s celebration,” Lo said.

Police searched the gunman’s home Sunday night for a motive as they continue to investigate the mass shooting.

Luna said Monday afternoon that no motive had been determined.

Police said they are still investigating a motive for the slayings.

The Associated Press contributed to this report.