Phoenix Police Chief Matt Giordano terminated a department sergeant Wednesday after investigators say the officer attended an off‑duty immigration protest at a Chandler high school while armed and wearing a face covering, and told fellow officers he planned to incite students into attacking him. The officer dismissed was identified as Sgt. Dusten Mullen. Chief Giordano described Mullen’s conduct during a January student walkout as “serious” and said it posed a threat to community trust, noting that rebuilding that trust has been a central focus of his tenure since he was sworn in last August following a national search.
Chandler police reports and body‑worn camera footage reviewed by investigators formed the basis of the internal action, officials said. The records show Mullen appeared at a protest involving Hamilton High School students that centered on immigration policies. According to body camera audio, Mullen told officers, “My plan is legitimately to let them all assault me and you guys arrest them all and I will keep it on film. I also have other people filming from distance.” The reports describe him as off‑duty, armed and wearing a face covering while he was present at the demonstration.
Split image used in coverage of the Phoenix Police firing: left, a uniformed officer addressing a public meeting; right, a masked man in a baseball cap who appeared at an anti‑ICE protest.
The move marks the first prominent termination announced by Giordano since he took command of the department, and law enforcement observers said the decision is likely intended to signal a tougher stance on accountability. Stan Kephart, a former Arizona police chief and a longtime law enforcement expert, said the firing sends a message both inside the ranks and to the wider community. “He’s a sergeant. He’s a supervisor. He’s the one that is looked to by his peers,” Kephart said, adding that the chief’s action was appropriate. “I think that the actual behavior and conduct of the chief is spot on. I would have done the same thing.”
Kephart and others noted that the Phoenix Police Department has been operating under heightened scrutiny since a yearslong Justice Department review documented a pattern of civil‑rights concerns, including excessive force, unlawful detentions and discrimination against minority communities, protesters and people experiencing homelessness. Giordano has repeatedly said that transparency, community trust and accountability are priorities for his administration, and supporters of the termination said decisive action is necessary to begin restoring confidence. “I think the chief is sending that message and I think it’s loud and clear. And quite frankly, I applaud him for doing his job,” Kephart said.
Officials and observers pointed to the explicit nature of Mullen’s statements as a key factor in the department’s response. Kephart said the officer’s presence while armed, together with the expressed intent to encourage others to attack him so they could be arrested and recorded, violated departmental policy. “The intention was clear. He was there, he was armed. And so that violates policy along with the intent to have others attack him,” Kephart said. Chief Giordano has framed the termination as part of broader efforts to hold officers accountable and to make clear that public safety responsibilities cannot be used as cover for conduct that risks community harm.
Mullen’s attorney disputes the findings of the internal probe and has characterized the officer’s actions as protected speech. Legal filings show Mullen has asked a federal court to block his termination, filing an emergency motion challenging the department’s decision. The Arizona Conference of Police and Sheriffs has also criticized the discipline, arguing it was based on protected off‑duty speech and that the internal investigation was flawed. Those legal and advocacy arguments set the stage for a court review that will determine whether the dismissal stands.
The dismissal adds a high‑profile personnel development to the department’s efforts to respond to the federal report and to reassess practices that federal investigators found problematic. Giordano, who took command last summer after a national search, has made restoring community trust a stated priority and has emphasized transparency and accountability as guiding principles for his leadership. The legal challenge from Mullen and the objections from policing organizations mean the termination is likely to remain in the public eye as officials, advocates and courts weigh the competing claims about discipline, free speech and policy violations.