Residents cheered and applauded prosecutors and police Tuesday as the alleged perpetrator of a deadly Fourth of July shooting rampage in a Chicago suburb was charged with seven counts of first-degree murder.

The accused gunman, 21-year-old Robert E. Crimo III, faces the prospect of life in prison with no chance of parole, as well as "dozens" more likely charges, said Lake County state's attorney Eric Rinehart.

Another round of whoops and cheers went up as Rinehart told a news conference, just steps from the scene of Monday's deadly shooting, that prosecutors will ask that Crimo be held without bail.

"What should have been a celebration of freedom has ended in despair for our community," Rinehart said, a battery of officials, investigators and police behind him.

"All of the people who died steps from here lost their freedom — all of it, every ounce of freedom that they had. The freedom to love, the freedom to learn and the freedom to live a full life.

"Their freedom matters too."

Behind him, at the corner of Central Ave. and Green Bay Rd., the detritus of an abandoned national holiday was still visible, a testament to the moment America's patriotic fervour dissolved into panic.

Seven people were killed and 38 people were injured Monday when a lone gunman, perched on a rooftop and disguised in women's clothing, opened fire on spectators while they were watching the Fourth of July parade pass through the core of this leafy suburb.

Upturned folding chairs, drink cups and a child's pink bicycle were still visible behind police barricades, the street lights festooned with rainbow flags and the Stars and Stripes.

#July4th #shooting suspect charged with seven counts of first-degree murder. #HighlandPark #Chicago #GunViolence

At the end of the street, a flagpole rose from the centre of the chaos, its massive U.S. flag hanging limply at half-mast.

Rinehart described the attack as premeditated and promised more charges related to the injured would be forthcoming, including attempted murder and aggravated battery.

And he delivered a pointed sermon about the need to reimpose a ban on assault weapons, something Congress accomplished in 1994 only to see the ban expire 10 years later.

"It lasted for 10 years, and studies have shown that mass shootings like what happened (Monday) went down during those 10 years," said Rinehart, himself a Highland Park resident.

"We should have that same ban in Illinois and beyond, in the entire country."

Earlier Tuesday, police revealed they visited the suspect's home twice in 2019.

Christopher Covelli, a spokesman for the Lake County Major Crime Task Force, said they first responded to Crimo's home in April 2019 after learning he had attempted suicide a week earlier.

Police spoke with his parents and the matter was dealt with by mental-health professionals as there wasn't any law-enforcement action to be taken at that time, he said.

The next interaction happened in September of that year, when a family member reported that Crimo said he was going to "kill everyone," and that he had a collection of knives.

Covelli said police responded to his home, where they removed 16 knives, a dagger and a sword, but there was no probable cause to arrest and no complaints were signed.

The Highland Park Police Department did immediately notify the Illinois State Police about the incident, he said.

"Police can’t make an arrest unless there is probable cause to make an arrest or somebody is willing to sign complaints regarding an arrest," he said.

"Absent of those things, police don’t have the power to detain somebody."

Crimo legally purchased five guns, including the rifle used in the attack and one found in a vehicle with him when he was arrested, as well as handguns and other firearms seized at his father's home Monday.

Authorities also on Tuesday released the identities of six of the seven victims: Katherine Goldstein, 64; Irina McCarthy, 35; Kevin McCarthy, 37; Jacquelyn Sundheim, 63; and Stephen Straus, 88, all from Highland Park; and Nicolas Toledo-Zaragoza, 78, of Mexico.

The violence in Highland Park came just six weeks after a deadly elementary school rampage in Uvalde, Tex., killed 19 children and two teachers, shocking — but not surprising — a country now utterly awash in staggering firepower.

Covelli said the community in Highland Park has been very helpful in providing information to law enforcement, but based on video surveillance, police believe a woman saw Crimo drop his rifle inside a red blanket immediately following the shooting.

He urged that witness to come forward and speak with investigators, as well as anyone else with relevant firsthand information.

Covelli said the suspect planned the attack for several weeks and wore women's clothing to conceal his facial tattoos and to blend into the crowd as he fled the scene.

He said the suspect brought a legally purchased high-powered rifle to the parade, climbed onto the roof of a business via a fire escape ladder and fired more than 70 rounds.

Video clips posted to social media showed the festivities collapsing into panic as revellers realized they were under fire and scrambled for cover.

After the attack, police said Crimo dropped his rifle and escaped, blending into the crowd as if he were an "innocent spectator" and walking to his mother's house, where he borrowed her car.

Police put out an alert with information about Crimo and the vehicle, and a member of the public who spotted the vehicle dialed 911 and officers were able to apprehend him.

The officer added there is no indication that anyone else was involved in the attack and a motive has not been determined. Police have no information that it was religiously or racially motivated, Covelli said, adding it appears to be "completely random."

In a tweet late Monday, Prime Minister Justin Trudeau offered condolences to the victims, their families and the Highland Park community.

They "wanted nothing more than to celebrate their country … but instead had their lives change forever," Trudeau tweeted.

"To the injured, and to the loved ones of the victims: Canadians are keeping you in our thoughts."

This report by The Canadian Press was first published July 5, 2022.

— With files from The Associated Press

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