Romanucci & Blandin files Wrongful Death Lawsuit Against City of Glendale, Arizona for Police Shooting of Dillon Siebeck

46-year-old man was peacefully sitting in a local park when officers confused him for a suspect and fired fatal shots

(PHOENIX, January 7, 2026) – Dillon Siebeck should be alive. An evening that began with Dillon minding his own business in Horizon Park in Glendale, Arizona, ended with Dillon being tragically and sloppily mistaken by police for a suspect in a nearby crime, leading an officer to fire multiple shots at Dillon, despite Dillon being unarmed and peaceful. Further, once Dillon was struck, police failed to render any medical aid to him for 19 minutes. Dillon needlessly and senselessly died that evening from his wounds.

Romanucci & Blandin announces the filing of a civil lawsuit on behalf of Dillon’s family for his wrongful death, which was the direct result of patterns and practices of excessive force in the Glendale Police Department (GPD). Officer Juan Gonzales’ decision to shoot at Dillon four times constituted deadly and excessive force, unjustified by any threat posed by Dillon or any threat reasonably perceived by Officer Gonzales.

Case Background

On January 8, 2025, at about 7 p.m., Glendale Police arrived at Horizon Park during the pursuit of a suspect for a domestic violence call. The suspect Police were seeking was a Hispanic man in his early 20s whose name was Angelo Diaz.

Dillon, who was twice this suspect’s age, did not resemble this suspect. Had GPD 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. 

Around 7:10 p.m., GPD officers suspected movement inside a white pick-up truck that was Diaz’s vehicle, but could not confirm the vehicle’s occupancy due to the vehicle’s tinted windows. GPD officers instructed the occupant to exit the vehicle with his hands raised, but took no action to confirm the vehicle’s occupancy. No one exited the vehicle, and 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.

Once Dillon was spotted in the park, no GPD officer took any step to confirm that Dillon was the person GPD was searching for. Officers, including Gonzales and Anderkin, simply assumed—without any reasonable basis—that Dillon was the person they were looking for simply because he was present in the park. 

Officers were standing behind police vehicles approximately 300 feet from Dillon. Officer Juan Gonzales was among the officers who set up to confront Dillon, lying down in front of a police vehicle hundreds of feet from Dillon. Sergeant Joshua Anderkin led the team to confront Dillon.

Despite the lack of physical similarity to their suspect, Officer Gonzales pointed an assault rifle at Dillon. 

Police used a PA system and instructed “Angelo” 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.

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.

Notwithstanding that numerous GPD officers were involved in the confrontation with Dillon and that numerous others were present at the park, neither Sergeant Anderkin nor any other GPD officer intervened after Officer Gonzales fired two shots at Dillon without justification. Neither Sergeant Anderkin nor any other GPD officer took any steps to stop or disarm Officer Gonzales, or to discourage him from shooting at Dillon.

Fourteen seconds after Officer Gonzales’ first volley of shots, he shot at Dillon two more times. No further instructions had been given to Dillon after the instructions given by Sergeant Anderkin during Officer Gonzales’ first volley of shots. At least one of the second volley of bullets fired by Officer Gonzales struck Dillon.

GPD officers eventually approached Diaz’s vehicle, where they found him dead from an apparently self-inflicted gunshot wound. Upon information and belief, Diaz shot himself before a GPD officer arrived on scene, and no gun, other than Gonzales’ rifle, was fired while GPD officers were on scene. 

Had GPD officers, including Officer Gonzales and Sergeant Anderkin, cleared their suspect’s vehicle before turning their attention to Dillon, they would have found Diaz incapacitated, and Dillon Siebeck would still be alive.

Failure to render lifesaving aid or call for emergency medical help

Once Dillon had been shot, Sgt. Anderkin did not provide medical attention or instruct any officer to provide medical attention to Dillon until more than 19 minutes after Dillon had been shot. Not only did Anderkin not radio for medical attention or instruct any officer to radio for medical attention to Dillon, but he also instructed officers to “hold” and not approach Dillon until the K9 unit arrived. Once officers did begin to approach Dillon, it took them a full 75 seconds to reach Dillon’s vicinity–an indication of just how far away Officer Gonzales and the other GPD officers were when Officer Gonzales shot Dillon.

Dillon died in Horizon Park as a result of being shot by Officer Gonzales, for which he received no timely medical aid.

Civil Lawsuit Details

The eight-count complaint was filed on December 31, 2025, in the U.S. District Court, District of Arizona, by Romanucci & Blandin, LLC, on behalf of Plaintiffs Arliss Siebeck, Dillon’s brother, and Helen Domme, Dillon’s mother.

Defendants named in the complaint are Juan Gonzales, Joshua Anderkin and the City of Glendale.

The Plaintiffs are represented by Founding Partner Antonio M. Romanucci, Senior Attorneys Benjamin A. Berkman and Joshua M. Levin from Romanucci & Blandin, LLC. The law firm of Lerner & Rowe also contributed to the case.

The lawsuit seeks a trial by jury.

Counts in the lawsuit include:

• COUNT I – 42 U.S.C. 1983 – Excessive Force
• COUNT II – 42 U.S.C. 1983 – Unlawful Seizure
• COUNT III – 42 U.S.C. 1983 – Failure to Render Aid
• COUNT IV – 42 U.S.C. 1983 – Failure to Intervene
• COUNT V – 42 U.S.C. 1983 – Failure to Supervise
• COUNT VI – 42 U.S.C. 1983 – Interference with Familial Relationship
• COUNT VII – 42 U.S.C. 1983 – Monell
• COUNT VIII – R.S. § 12-611 – Wrongful Death

“The wrongful death of Dillon Siebeck is, unfortunately, a textbook example of excessive force violations by police. This man was unarmed and did not present any type of threat to the officers. He was not a suspect in a crime and was minding his own business. Dillon’s loss of life was completely needless. We will pursue full accountability for what happened that evening in Glendale,” said Antonio M. Romanucci, Founding Partner of Romanucci & Blandin.

“Not a single Glendale police officer intervened after one of their fellow officers fired two entirely unjustified shots at an unarmed man from hundreds of feet away. Their inaction enabled the officer to fire two more entirely unjustified shots at Dillon, killing him. 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 Senior Attorney Benjamin A. Berkman, Romanucci & Blandin.

“Dillon loved to make people laugh and would literally do anything for the people he cared about. Our family deeply misses his huge heart, and his death has changed us forever. What upsets us is that what happened to Dillon could happen to anyone. It could have been anyone in the park at that time, and unfortunately, it was my brother. We sincerely hope this lawsuit can bring transparency and accountability for his loss, but also can create change for the community so no family ever has to go through this again,” said Plaintiff Arliss Siebeck, Dillon’s brother.

Learn more about Romanucci & Blandin from our website.

ABOUT ROMANUCCI & BLANDIN, LLC

Romanucci & Blandin is a Chicago-based national trial practice committed to fighting for victims of negligence, abuse and wrongful death through impact litigation. For more than 25 years, we have secured more than $1 billion in verdicts and settlements for our clients - many for millions of dollars or record-setting awards. Our experience ranges from mass shootings, civil rights and police misconduct to medical malpractice, sexual abuse, motor vehicle accidents or workplace injury cases involving individual or institutional negligence. Romanucci & Blandin is a valuable legal resource to individuals and groups of people who have been injured by others’ wrongdoing. Referring attorneys and clients say several factors distinguish our firm: Our record of success, depth of experience, talented and dedicated legal team, tireless preparation, and strategic use of communications to fight for the rights of those whose lives have been changed forever. We differ from other personal injury firms in that our work does not stop when a verdict or settlement is secured. Our clients’ experiences often inspire us to commit resources to transforming lives and communities. For more information about Romanucci & Blandin, please visit: www.rblaw.net.