Matthew Alder Charged in No Kings Protest Shooting Death

Matthew Alder is the 43-year-old Utah military veteran charged with manslaughter in the No Kings protest shooting that killed bystander Arthur “Afa” Ah Loo in downtown Salt Lake City on June 14, 2025. Alder was serving as an armed volunteer on an unofficial safety team when he fired three shots at another armed attendee he believed was about to attack the crowd. The third shot struck Ah Loo, a 39-year-old fashion designer walking through the march with a cellphone and a protest sign. Alder faces up to 15 years in prison if convicted, and his criminal case remains pending alongside a wrongful death lawsuit filed by Ah Loo’s widow.

What Happened at the Salt Lake City Protest

An estimated 4,000 people gathered at Pioneer Park on the evening of June 14, 2025, and marched toward the Wallace F. Bennett Federal Building as part of the nationwide “No Kings” demonstrations against the Trump administration.¹ Shortly before 8:00 p.m., Alder and another safety volunteer spotted 24-year-old Arturo Roberto Gamboa near the crowd assembling an AR-15 style rifle he had pulled from a backpack.²

Alder later told investigators he yelled at Gamboa to stop but that Gamboa kept moving toward the crowd, which “scared the hell out of me.”³ He fired three times. The first shot hit Gamboa. The third traveled over the heads of people in the crowd and struck Afa Ah Loo in the temple, killing him. Ah Loo, a father of two and former Project Runway contestant, had been walking in the middle of State Street filming with his phone and carrying a sign that read “The world is watching.”⁴

A second safety volunteer who was with Alder told investigators he did not believe it was safe to fire.⁵

Who Matthew Alder Is

Alder is a military veteran and a member of Armed Queers SLC, an LGBTQ organization that describes itself as “dedicated to the defense, and success, of oppressed people’s movements.” According to the group’s own statement, Armed Queers SLC was brought in as a “secondary de-escalation team” only two days before the protest because organizers were worried about agitators, and the group said it was given “very few details and transparency about the de-escalation plan.”⁶

Salt Lake City police confirmed the protest permit did not disclose the use of armed security.⁷ The national 50501 organization behind the No Kings movement, which maintained a strict no-weapons policy for all events, disavowed its Utah chapter after the shooting, saying the local event “did not meet” that policy.¹

Why Alder Was Charged With Manslaughter

The investigation took nearly six months. The Salt Lake City Police Department turned its findings over to Salt Lake County District Attorney Sim Gill without a formal charging recommendation.⁸ On December 3, 2025, Gill announced a single count of manslaughter, a second-degree felony that carries up to 15 years in prison.⁹

Gill drew a careful line between Alder’s first two shots and the fatal third one. Under Utah law, he said, Alder had a right to carry a firearm and to use lethal force against a perceived threat. The third shot, fired over the heads of people in a large crowd, was where prosecutors concluded he crossed into criminal recklessness. “While you may have a right to use lethal force, that doesn’t mean that that lethal force can be used in a reckless manner,” Gill said.¹⁰

Laura Ah Loo, Afa’s widow, said she was “grateful” that the office reached what she called a “moral and just” decision, describing the charge as a “significant first step.”¹⁰

Alder’s Defense and the Justification Hearing

Alder is represented by attorney Philp Wormdahl, who has publicly said Alder “did not break any law.”¹¹ The defense plans to invoke a 2021 Utah self-defense law that allows a judge to dismiss charges at a pretrial “justification hearing” unless prosecutors can prove by clear and convincing evidence that the use of force was unjustified.

“Obviously, on that date in June, it was a great tragedy,” Wormdahl told reporters. “But given the evidence that I’m aware of now, the lawyers who are involved in this are all uber-confident that no reasonable person could find that he wasn’t justified in his actions.”¹¹ In the parallel civil case, Alder’s defense has argued that Gamboa bears responsibility for what happened.¹²

Alder made his first court appearance on January 6, 2026, before Commissioner Todd Olsen in Third District Court in Salt Lake City.¹³ Reporting from June 2026 indicated the charge could be resolved at a justification hearing, through a plea to a lesser charge, or at trial. No trial date had been set.¹⁴

The Wrongful Death Lawsuit

In March 2026, Laura Ah Loo filed a wrongful death lawsuit in Third Judicial District Court of Salt Lake County, seeking damages exceeding $300,000 for economic losses, medical and funeral expenses, and lost companionship.¹⁵ The suit names Alder, event organizer Utah 50501, permit applicant Michael Andamen, and several other individuals.

The complaint alleges the event was “ill-prepared,” that Utah 50501 encouraged participants to carry concealed weapons, and that armed security from Armed Queers SLC was requested only one day before the protest. Against Alder specifically, it alleges he failed to clear the area behind his target and failed to properly distinguish between a real and a perceived threat.¹⁵ The family is represented by Jim McConkie of Parker and McConkie and former federal prosecutor Richard Lambert.¹⁶

What Happened to the Man Alder Shot At

Arturo Roberto Gamboa, the 24-year-old man Alder was firing at, was initially booked on suspicion of murder and held for about a week before his release on June 20, 2025. On the same day Alder was charged, DA Gill announced Gamboa would face no charges, citing insufficient evidence he had broken any law, though Gill called his conduct “alarming and irresponsible.”⁵ Under Utah law, Gamboa was lawfully permitted to openly carry the rifle.

Gamboa later said he had not fired a single shot and that his rifle had no ammunition. He said he had open-carried at protests as a form of self-defense after seeing “outside agitators” with weapons at earlier demonstrations, and he said he had been “treated as a psychopathic villain.”¹⁷

Utah Gun Law and the Political Aftermath

The case sits inside Utah’s permissive firearms framework. Utah is a constitutional-carry state that allows open and concealed carry without a permit for people 21 and older, and a stand-your-ground state with no duty to retreat when a person reasonably believes deadly force is necessary to prevent death or serious injury.¹⁸ No state law prohibits open carry of long guns at political protests.

Governor Spencer Cox said after the shooting that the Utah Department of Public Safety had warned protest organizers “many months” in advance that using armed peacekeepers was a “bad idea,” but he said he did not believe the state should legislate against open carry at protests: “I’m a big believer in the Second Amendment.”⁸

Two Democratic legislators introduced bills during the 2026 session in response to the shooting. Rep. Verona Mauga of Taylorsville proposed prohibiting open carry within 500 feet of large gatherings such as protests; the bill received no committee hearing or floor vote. Sen. Kathleen Riebe of Cottonwood Heights introduced a bill to clarify Utah’s self-defense law in cases involving bystander casualties; it failed in the state Senate after opposition from gun rights advocates and defense attorneys.¹² Gill himself has called for legislative action on gun restrictions at public gatherings, pointing to the risk of “misunderstandings” when multiple armed people converge at chaotic events.¹⁰

1
The Salt Lake Tribune. No Kings Timeline
2
Salt Lake City Police Department. SLCPD Provides Update on Downtown Shooting Investigation
3
NBC News. Safety Volunteer Charged With Manslaughter in Shooting at Salt Lake City No Kings Rally
4
The New York Times. No Kings Protest Shooting
5
CNN. Matthew Alder Charged in No Kings Protest Shooting
6
Utah News Dispatch. Peacekeeper in Salt Lake City No Kings Shooting Is Military Veteran
7
KUER. No Kings Safety Volunteer Who Fired His Weapon Is a Veteran, Organizers Say
8
News From the States. Utah Gov. Cox Says State Warned No Kings Organizers It Was Bad Idea to Use Peacekeepers
9
The New York Times. No Kings Protest Shooting Salt Lake City Charges
10
KUER. No Kings Peacekeeper Charged With Manslaughter in Fatal Salt Lake City Shooting
11
News From the States. Lawyer for Armed Volunteer Charged in No Kings Killing Says He Didn’t Break Any Laws
12
Utah News Dispatch. Afa Ah Loo Widow, No Kings Shooting, Calls for Responsible Gun Laws
13
ABC4. No Kings Shooter Court Appearance
14
The Salt Lake Tribune. Legal Case Against Matthew Alder
15
Fox 13 Now. Ah Loo Family Files Lawsuit Against Protest Peacekeeper, Event Organizers
16
KUER. Widow in SLC’s Fatal No Kings Shooting Questions Why No One Has Been Charged
17
KUER. Why Arturo Gamboa Brought a Rifle to SLC’s No Kings Protest, in His Words
18
Utah News Dispatch. Utah Gun Laws in No Kings Shooting: Open Carry and Self-Defense