Twelve people were injured Sunday afternoon in Boulder after a 45-year-old man allegedly threw a Molotov cocktail at a group participating in a peaceful demonstration on the Pearl Street Mall.

What happened?

The attack occurred just before 1:30 p.m. near 13th and Pearl streets during a weekly event called the “peaceful humanitarian walk for hostages,” organized by the group Run For Their Lives, which raises awareness about Israeli hostages held in Gaza.

Witnesses say a man was waiting near the historic courthouse with bottles in hand. He allegedly shouted “free Palestine” and threw what officials described as a makeshift flamethrower or Molotov cocktail into the crowd.

Who are the victims?

Twelve people between the ages of 52 and 88 were injured. Initially, Boulder Police said eight people were injured. On Monday afternoon officials confirmed there were four additional victims. One of the victims is a Holocaust survivor, according to a friend who spoke to 9NEWS.

Some victims suffered burns and were transported to Denver-area hospitals. UCHealth University of Colorado Hospital in Aurora confirmed it received three patients who were airlifted from the scene.

The Boulder Police Department on Monday said none of the burn victims had died.

Who is the suspect in the Boulder attack?

Police apprehended 45-year-old Mohamed Sabry Soliman, an Egyptian citizen. He was taken to a hospital for evaluation before being booked into the Boulder County Jail on $10 million bond. Authorities said Soliman will remain in custody during the investigation.

Soliman was charged with a federal hate crime, according to documents provided by the Federal Bureau of Investigation. The offense carries possible sentence of 10 years in prison and a $250,000 fine.

Witnesses initially described the attacker as a man dressed as a gardener. Boulder Police Chief Stephen Redfearn said Soliman was arrested without incident.

Officials said Soliman resides in Colorado Springs.

White House Deputy Chief of Staff Stephen Miller on Sunday said on social media that Soliman had “illegally overstayed” a tourist visa.

“He was granted a tourist visa by the Biden Administration and then he illegally overstayed that visa,” Miller wrote in a post on X. “In response, the Biden Administration gave him a work permit.”

Soliman was living in the U.S. illegally after having entered the country in August 2022 on a B2 visa that expired in February 2023, Department of Homeland Security Assistant Secretary Tricia McLaughlin said in a post on X. McLaughlin said Soliman filed for asylum in September 2022 and was granted a work authorization in March 2023 that had expired. DHS did not immediately respond to requests for additional information.

Public records listed Soliman as living in a modest rented townhouse in Colorado Springs, where local media outlets reported federal law enforcement agents were on the scene Sunday.

He said in his interview with police that his goal was to “kill all Zionists,” the FBI said, and that he intentionally targeted the group and knew they would be assembled on Sunday afternoon.

“He stated that he had been planning the attack for a year and was waiting until after his daughter graduated to conduct the attack,” the arrest affidavit says.

How did authorities respond?

Authorities evacuated a perimeter from Broadway to 16th Street and Pine to Walnut streets on Sunday. The investigation remains active and evolving.

Officials speaking anonymously to CNN said 16 additional Molotov cocktails were found in the area.

The FBI is treating the incident as an act of terrorism. FBI Special Agent in Charge Mark Michalek said the suspect’s actions and statements are part of an ongoing federal investigation. FBI Director Kash Patel and Deputy Director Dan Bongino both confirmed on social media that federal agents are involved and are investigating it as an “ideologically motivated” attack.

Colorado Attorney General Phil Weiser called it a likely hate crime, given the targeted nature of the group. Boulder District Attorney Michael Dougherty said charges are pending and could be brought at the state or federal level.

Gov. Jared Polis condemned the incident as a “heinous act of terror” and has ordered additional security at Jewish places of worship across the state.

A street southwest of the intersection of Constitution Avenue and Marksheffel Road in Colorado Springs was blocked off by law enforcement Sunday night. The investigation was related to the Boulder attack, according to the FBI. The El Paso County Sheriff’s Office said it was assisting with the investigation but deferred other questions to the FBI.

What are officials saying?

President Donald Trump: “Yesterday’s horrific attack in Boulder, Colorado, WILL NOT BE TOLERATED in the United States of America. He came in through Biden’s ridiculous Open Border Policy, which has hurt our Country so badly. He must go out under “TRUMP” Policy. Acts of Terrorism will be prosecuted to the fullest extent of the Law. This is yet another example of why we must keep our Borders SECURE, and deport Illegal, Anti-American Radicals from our Homeland. My heart goes out to the victims of this terrible tragedy, and the Great People of Boulder, Colorado!”

Police Chief Stephen Redfearn: “This was a beautiful Sunday afternoon in downtown Boulder on Pearl Street, and this act is unacceptable.”

District Attorney Michael Dougherty: Promised to “hold the attacker fully responsible” and “secure justice for the victims.”

Gov. Jared Polis: “Hate-filled acts of any kind are unacceptable.”

Attorney General Phil Weiser: “Violence is never the answer to settling differences. Hate has no place in Colorado.”

City Council Member Tara Winer: Called it likely an antisemitic attack; some of the victims are her personal friends.

Denver Mayor Mike Johnston: “Our hearts are with Boulder as we mourn the innocent victims of senseless violence. Denver Police Department is in contact with Boulder PD to provide any support they need. Hate has no place in Colorado.”

What happens next?

The Boulder County Jail lists Soliman as being held on $10 million bond on a range of possible charges that include first-degree murder with extreme indifference, crimes against an at-risk adult, using an incendiary device during a felony and first-degree assault.

Soliman was due in a Boulder County court on Monday. The Denver Gazette will provide coverage from the appearance.

This is a developing story. More details will be shared as they become available.

Denver Gazette reporters Marco Cummings and Noah Festenstein, freelance reporter Carol McKinley, and our news partners 9NEWS contributed to this report.