Sergeant Dusten Mullen of the Phoenix Police Department has filed a federal lawsuit against the City of Phoenix, Police Chief Matt Giordano and Councilwoman Anna Hernandez, asking a judge to stop a pre-termination hearing and freeze any disciplinary action. Mullen was placed on administrative leave after an off-duty confrontation at a student anti-ICE walkout in Chandler, and he claims the department retaliated against him and violated his due process rights. In the complaint, he seeks a temporary restraining order and a preliminary injunction ahead of a May 4 pre-termination hearing.
What the complaint says
According to court filings posted on Justia Dockets, Mullen and the Arizona Conference of Police and Sheriffs filed the complaint April 27, 2026, invoking 42 U.S.C. § 1983 and asking the court for emergency relief. The docket lists a motion for a temporary restraining order and preliminary injunction and shows summonses issued to Chief Giordano, Councilwoman Anna Hernandez and the City of Phoenix.
Allegations from the protest
As reported by FOX 10 Phoenix, the complaint and a Chandler police report say Mullen went to the Jan. 30 student demonstration at Hamilton High in Chandler while masked and openly carrying a handgun and two extra magazines. The police record quoted Mullen as saying, "my plan is legitimately to just let them all assault me and you guys arrest them all, and I'll keep it on film," and says he told students to "grow up and act like adults" while saying his goal was to get protesters arrested.
Department response and leave
Chief Matt Giordano placed Mullen on administrative leave in April while the Professional Standards Bureau examines the incident, the department has said. KJZZ reports the chief said officers are held to a higher standard and that the review is ongoing.
Defense and process concerns
Mullen's attorney, Steve Serbalik, has pushed back, saying his client was exercising protected First Amendment rights and that he did not incite an attack, according to Arizona's Family. The complaint, detailed in reporting by FOX 10 Phoenix, also alleges the Professional Standards Bureau canceled a follow-up interview on April 20 and that Lieutenant Brian Thatcher provided "exonerating" materials to investigators, claims Mullen says deprived him of a full investigation.
Next steps
Mullen's federal complaint asks a judge to vacate the May 4 pre-termination hearing and to bar any disciplinary action while his constitutional claims move forward. Court records on Justia Dockets confirm the April 27 filing and the motion for emergency relief; the case is now pending in federal court.
Why it matters
The lawsuit puts off-duty speech, officer accountability and departmental discipline in the spotlight at a time when Phoenix has faced federal scrutiny over protest-related practices. Arizona's Family notes the department implemented new First Amendment training after a Justice Department finding, and attorneys say the pending federal case will test whether internal procedures were followed.
