Police quickly responded to an active shooter in Dayton's Oregon District

Second mass shooting in less than 24 hours left nine dead. 20 killed in El Paso

The suspect in the Dayton shootings is dead

DAYTON, Ohio – Lifting their voices in song and prayer, thousands of Dayton residents gathered downtown to mourn Sunday night, less than 24 hours after a gunman killed at least nine people in a downtown entertainment district.

As the sound of Amazing Grace echoed off the buildings and an American flag waved in the evening breeze, Daytonians cheered their first responders and gave thanks the bloodshed wasn’t worse. Authorities say police responding to the shooting neutralized the gunman, identified as Connor Betts, 24, within 30 seconds.

“We are here to heal tonight,” Dayton Mayor Nan Whaley told the crowd that gathered Sunday night near where the shooting occurred. As darkness fell, hundreds of candles flickered in the hands of community members who vowed Dayton would grow stronger.

Audience members repeatedly interrupted the speakers to demand action by lawmakers: "What do we want? Gun control! When do we want it? Now!"

Authorities said Betts, of nearby Bellbrook, opened fire with a rifle early Sunday in the city’s Oregon District. Among the dead was his 22-year-old sister, Megan. At least 27 people were injured.

Get the latest updates:Everything we know about the shooting rampage in Dayton

The assault was the nation's second mass shooting in less than 24 hours. On Saturday, a 21-year-old gunman killed 20 and wounded 26 others at a Walmart in El Paso, Texas.

Speaking to reporters Sunday afternoon, President Donald Trump said mental illness played a role in both shootings. He said his administration would have more to say Monday morning.

"But this is also a mental illness problem, if you look at both of these cases, this is mental illness," Trump said. "These are people really that are very, very seriously mentally ill."

Dayton Police Chief Richard Biehl said officers patrolling the area heard gunshots and saw people running. They engaged Betts, who was armed with an assault-style rifle, within 20 seconds, and he was "neutralized" approximately 30 seconds after he fired his first shot, Biehl said.

Biehl said it was too soon to determine a motive for the shooting. He released video showing the pandemonium as people fled and officers moved in when the shooter approached Ned Peppers Bar before going down.

"Had this individual made it through the doorway of Ned Peppers with that level of weaponry, there would have been a catastrophic injury and loss of life," Biehl said.

Assistant Chief of Police Matt Carper said security footage in the area was being studied and hundreds of witnesses were being interviewed. The FBI was joining the investigation, he said. The gunman appeared to have acted alone in his assault on the trendy stretch of bars and restaurants, Carper said.

"Downtown Dayton is a very safe area," Carper said. “This is unheard of and very sad. It’s a very tragic evening.”

Whaley lauded police for their quick response. "In less than a minute, Dayton first responders neutralized the shooter," she said. "This is a terribly sad day for the city, but I am amazed by the (police) response."

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The latest on El Paso:Everything we know about the victims, the suspect

Witnesses described a chaotic, bloody scene as people struggled to comprehend what was happening and then scrambled for cover.

"All of a sudden we heard what sounded like fireworks," said Morgan Olivia Beck, 22, who was drinking with friends on the balcony of a nearby tavern when the shooting started. "But they wouldn't stop."

When it was over, bodies were strewn across the street and sidewalk. Shoes from fleeing bar patrons were scattered in a parking lot. The gunman was white; six of those killed were black.

Nikita Papillion, 23, said she was dancing at Ned Peppers Bar when the shooting started. She fled the building, running past people who had been shot.

“There were two bodies to the right; six steps away there was a third girl on the ground,” Papillion said. She said she did not know the girl but had complimented her outfit earlier that night.

Brandon White, 29, leaned on the hood of his car near a police barricade. He said his aunt called, saying his cousin was among those shot.

"Me and my mom rushed down here, and we’re just waiting to hear something,” he said. "There are cops all over the place down here on the weekend. He must have had a death wish or something."

Bellbrook Police Chief Doug Doherty said Betts' parents were "floored" by the news.

"We don't know the why. We don't know the whats, any of those questions," Doherty said. "But we do know that there is a mom and dad down there that are really hurting."

Hours after tweeting out condolences to families of victims in El Paso, Trump tweeted that the FBI was aiding the investigations in El Paso and Dayton. He lauded the efforts of first responders in both cities and ordered flags flown at half staff to honor the victims.

"God bless the people of El Paso Texas," he tweeted. "God bless the people of Dayton, Ohio."

In a statement, NRA spokesman Andrew Arulanandam thanked first responders for their efforts, and added: “The NRA is committed to the safe and lawful use of firearms by those exercising their Second Amendment freedoms. We will not participate in the politicizing of these tragedies but, as always, we will work in good faith to pursue real solutions that protect us all from people who commit these horrific acts.”

The Dayton wounded were rushed to several areas hospitals, and one was listed in critical condition. The dead included four women and five men: Lois Oglesby, 27; Saeed Salah, 33; Logan Turner, 30; Nicholas Cumer, 25; Thomas McNichols, 25; Beatrice Warren-Curtis, 36; Monica Brickhouse, 39; and Derrick Fudge, 57.

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Ohio Lt. Gov. Jon Husted graduated from the University of Dayton and represented the city as a lawmaker. "Over the years I have been to the Oregon District in many times. To see this happen there is devastating," he tweeted.

Ohio Gov. Mike DeWine said in he was "heartbroken" over the attack.

"We join those across Ohio and this country in offering our prayers to victims and their families," he said.

Bacon reported from McLean, Va. Contributing: Chris Woodyard and Chrissie Thompson, USA TODAY; P. Kim Bui and Robert Anglen, The Arizona Republic