The gunman who attacked an Independence Day parade in suburban Chicago fired more than 70 rounds with an AR-15-style gun that killed at least six people, then evaded initial capture by dressing as a woman and blending into the fleeing crowd, police said Tuesday.

A spokesman for the Lake County Major Crime Task Force told a news conference that the suspected shooter, who was arrested late Monday, used a high-powered rifle “similar to an AR-15” to spray bullets from atop a commercial building into a crowd that had gathered for the parade in Highland Park, a close-knit community on the shores of Lake Michigan that has long drawn the rich and sometimes famous.

More than 30 people were wounded in the attack, which task force spokesman Christopher Covelli said the shooter planned for several weeks.

Investigators who have interrogated the suspect and reviewed his social media posts have not determined a motive for the attack or found any indication that he targeted anyone by race, religion or other protected status, Covelli said.

Authorities have not filed criminal charges.

Earlier in the day, FBI agents peeked into trash cans and under picnic blankets as they searched for more evidence at the site where the assailant opened fire. The shots were initially mistaken for fireworks before hundreds of revelers fled in terror.

A day later, baby strollers, lawn chairs and other items left behind by panicked parade goers remained inside a wide police perimeter. Outside the police tape, some residents drove up to collect blankets and chairs they abandoned.

David Shapiro, 47, said the spray of gunfire quickly turned the parade into “chaos.”

“People didn’t know right away where the gunfire was coming from, whether the gunman was in front or behind you chasing you,” he said Tuesday as he retrieved a stroller and lawn chairs.

The shooting was just the latest to shatter the rituals of American life. Schools, churches, grocery stores and now community parades have all become killing grounds in recent months. This time, the bloodshed came as the nation tried to find cause to celebrate its founding and the bonds that still hold it together.

“It definitely hits a lot harder when it’s not only your hometown but it’s also right in front of you,” resident Ron Tuazon said as he and a friend returned to the parade route Monday evening to retrieve chairs, blankets and a child’s bike that his family abandoned when the shooting began.

“It’s commonplace now,” Tuazon said. “We don’t blink any more. Until laws change, it’s going to be more of the same.”

A police officer pulled over Robert E. Crimo III north of the shooting scene several hours after police released his photo and warned that he was likely armed and dangerous, Highland Park Police Chief Lou Jogmen said.

Authorities initially said Crimo, whose father once ran for mayor of Highland Park, was 22, but an FBI bulletin and Crimo’s social media said he was 21.

President Joe Biden on Tuesday ordered American flags be flown at half-staff through Saturday as a “mark of respect for the victims of the senseless acts of gun violence perpetrated on our Independence Day.”

The shooting occurred at a spot on the parade route where many residents had staked out prime viewing points early in the day.

Among them was Nicolas Toledo, who was visiting his family in Illinois from Mexico. He was shot and died at the scene, his granddaughter, Xochil Toledo, told the Chicago Sun-Times. Also killed was Jacki Sundheim, a lifelong congregant and “beloved” staff member at nearby North Shore Congregation Israel, which announced her death on its website.

Police have not released details about the victims, but Toledo’s granddaughter told the Sun-Times that Toledo had spent most of his life in Morelos, Mexico. Xochil Toledo said she remembers looking over at her grandfather, who was in his late 70s, as a band passed them.

“He was so happy,” she said. “Happy to be living in the moment.”

Xochil Toledo said her father tried to shield her grandfather and was shot in the arm. Her boyfriend also was shot in the back and taken to a hospital.

Sundheim had spent decades on the staff at North Shore Congregation Israel, teaching at the congregation’s preschool and later coordinating events, “all of this with tireless dedication,” the congregation said in its statement announcing her death.

“Jacki’s work, kindness and warmth touched us all,” the statement said.

NorthShore University HealthSystem said it treated 39 people at four of its hospitals after the shooting. Nine people, ranging from 14 to 70, remain hospitalized Tuesday. One patient, a 69-year-old man, was in critical condition from a gunshot wound.

Since the start of the year, the U.S. has seen 15 shootings where four or more people were killed, including the one in Highland Park, according to The Associated Press/USA TODAY/Northeastern University mass killing database.

Highland Park Police Commander Chris O’Neill said the gunman apparently fired from a rooftop where he was “very difficult to see.” He said the rifle was recovered at the scene. Police also found a ladder attached to the building.

Covelli said Crimo legally purchased the gun in Illinois within the past year.

In 2013, Highland Park officials approved a ban on assault weapons and ammunition magazines of more than 10 rounds. A local doctor and the Illinois State Rifle Association quickly challenged the liberal suburb’s stance. The legal fight ended at the U.S. Supreme Court’s doorstep in 2015 when justices declined to hear the case and let the suburb’s restrictions remain in place.

Crimo, who goes by the name Bobby, was an aspiring rapper with the stage name Awake the Rapper, posting on social media dozens videos and songs, some ominous and violent.

In one animated video since taken down by YouTube, Crimo raps about armies “walking in darkness” as a drawing appears of a man pointing a rifle, a body on the ground and another figure with hands up in the distance.

Crimo’s father, Bob, a longtime deli owner, sought the mayor’s office in 2019, calling himself “a person for the people.”

The community of about 30,000 on Chicago’s affluent North Shore has mansions and sprawling lakeside estates and was once home to NBA legend Michael Jordan.

Shapiro, the Highland Park resident who fled the parade with his family, said his 2-year-old son woke up screaming later that night.

“He is too young to understand what happened. But he knows something bad happened,” Shapiro said. “That’s chilling.”

(AP)