Wrongful death lawsuit filed a year after deadly Glendale police shooting

GLENDALE, Ariz. - The City of Glendale has issued a statement after it was announced that a lawsuit was filed against the city in connection with a deadly police shooting.

The backstory:

Glendale Police say the incident began at around 7:00 p.m. on Jan. 8, 2025, when officers responded to a domestic violence call near 47th and Glendale Avenues.

Once at the scene, officers encountered a woman who said she had been threatened by a man with a gun. The man fled the area in a vehicle before the officers arrived.

"Shortly after, a vehicle matching that description was located near 47th Avenue and Diana," police said. "Officers also found an individual outside the vehicle matching the suspect description."

Police say officers ordered the man to show his hands. He initially complied.

"At one point, officers say the individual dropped their hands and reached for something and that’s when one officer fired a shot at that individual," police said.

Officials said the suspect, Dillon Siebeck, was pronounced dead at the scene.

In May 2025, we spoke with the woman who made the domestic violence call to police that evening.

Gisselle Borquez said she did not know Siebeck, and that she called 911 for help to report her partner for domestic violence.

When officers arrived, however, they believed Siebeck was Borquez's partner.

"Dillon had nothing to do with the situation. I mean, he was just at a park. So now you can't even sit at a park without worrying that, you know, just because something else is going on around you, now you could be involved and you could be murdered? I'm just so sorry to his family that they have to deal with that," Borquez said.

What We Know Now:

In a statement released on Jan. 7, 2026, a law firm named Romanucci & Blandin announced that they have filed a lawsuit on Dec. 31, 2025 at the U.S. District Court in the District of Arizona.

Officials with the law firm said the suit was filed on behalf of Siebeck's brother and mother. It names the City of Glendale and two men - Joshua Anderkin and Juan Gonzales - as defendants. Anderkin was a sergeant at the time of the shooting, while Gonzales was an officer at the time.

Dig deeper:

A spokesperson with the law firm identified the man who was the subject of Borquez's 911 call as a Hispanic man in his early 20s named Angelo Diaz. They said Glendale officers spotted Diaz's pick-up truck at a park, and while they suspected movement inside the truck, they could not confirm if anyone was inside due to tinted windows.

"Without confirming or dispelling the vehicle’s occupancy, GPD officers shifted their attention to Dillon, who was sitting on a picnic table in the park," a portion of the law firm's statement reads. "Dillon, who was twice this suspect’s age, did not resemble this suspect. Had [Glendale Police Department] officers, including Officer Gonzales and Sergeant Joshua Anderkin, compared Dillon to their suspect’s physical description, they would have found that Dillon was not their suspect."

Lawyers for Siebeck's brother and mother said officers told "Angelo" over a PA to put his hands up and walk towards the officers.

"Dillon was unarmed and did not make verbal or physical threats to anyone or any property at any time," the lawyers wrote. "As Anderkin instructed ‘Angelo’ over the PA to keep his hands on his head, Officer Gonzales shot at Dillon twice with his assault rifle. Neither Officer Gonzales nor any other GPD officer gave Dillon a warning that they would shoot prior to Officer Gonzales firing at Dillon."

Siebeck, per the lawyers, was shot at two more times after the first gunfire volley.

"At least one of the second volley of bullets fired by Officer Gonzales struck Dillon," read a portion of the statement.

The lawsuit also alleges that Anderkin did not provide medical attention to Siebeck following the shooting, nor did he instruct any officer to give Siebeck medical attention until over 19 minutes after the shooting.

"The wholesale inaction of the Glendale police officers on scene in Horizon Park that night reflects a department where excessive force is tolerated. We are not only calling for justice for Dillon Siebeck, but also for systemic changes to the department that will bring it in line with Constitutional policing standards that the community deserves," said Attorney Benjamin A. Berkman with the firm.

The other side:

In their statement, Glendale Police said they "do not comment on any pending litigation," going on to say they will not be making any statements or grant interview requests.

However, police did release information as to the status of the officers involved in the incident.

Officials said with Gonzalez, Peoria Police investigated the deadly shooting and forwarded their findings to the Maricopa County Attorney's Office, which subsequently decided to not charge him.

While Gonzalez was not charged, Glendale Police said they, along with the city, ultimately chose to fire him because they felt the shooting "was outside of policy and keeping him as public safety officer could potentially be a safety risk to our community."

We received a copy of the letter that was sent to Gonzales notifying him of the results of his appeal of the firing. It states that while Glendale's Personnel Board voted not to sustain the firing, City Manager Kevin Phelps decided to uphold the firing.

"Your actions on January 8, 2025, were not within City policy and directly resulted in the death of an innocent victim, therefore, I cannot in good conscience allow you to resume your duties and responsibilities as a Glendale Police Officer," a portion of the letter reads.

The letter also states that Gonzalez was disciplined in 2022 for failing to properly handle, display, and use his gun, and that the City Manager's action "concludes [Gonzales'] appeal rights with the City of Glendale" regarding the firing.

"As for Sgt. Josh Anderkin, he remains an active member of the Glendale Police Department," read a portion of the statement. "As with pending litigation, we do not comment on personnel situations."