The off-duty officer is under internal investigation after police records said he confronted student protesters while armed and masked.
CHANDLER, AZ — An armed, masked man who confronted students during a Jan. 30 anti-ICE walkout outside Hamilton High School has been identified as Phoenix Police Sgt. Dusten Mullen, whose conduct is now under internal investigation.
The identification changes the weight of an episode that had already stirred concern in Chandler, where a teenage girl was arrested during the protest and a white SUV later pushed through part of the crowd. Phoenix police say Mullen remains employed while the department’s Professional Standards Bureau reviews what happened. The case now reaches beyond a tense school demonstration into questions about police conduct, off-duty behavior and how a veteran sergeant inserted himself into a protest involving minors.
Police said the protest unfolded as hundreds of students took part in demonstrations tied to immigration enforcement issues across the Valley on Jan. 30. At Hamilton High, officers assigned to monitor student safety noticed a man in a full-face mask carrying a handgun and arguing with demonstrators. According to a Chandler police report later obtained by local news outlets, students believed the man was connected to ICE and grew more agitated as they chanted and followed him. Officers told him his presence was creating a volatile situation and urged him to move elsewhere. The report said the man resisted leaving and, at one point, was calling for other armed supporters to come to the area. Later reporting identified that man as Mullen, an off-duty Phoenix sergeant. When Chandler officers approached him, the report said, he complained that students’ flags had hit his vehicle. One officer wrote that he had not seen flags strike the car.
The same report recorded a statement that has become central to the fallout. As officers walked with him toward a vehicle, the report said, Mullen told police that his “plan” was to let the students assault him, record it and have them arrested. Another section of the reporting said he also mentioned supporters were on the way, some armed with rifles. During the confrontation, a girl was accused of throwing what officers first described publicly as a water bottle at the masked man. Later reporting said the allegation was narrowed to a cup of water. The teen was detained on suspicion of assault and disorderly conduct after the man said he wanted charges. Chandler police said the armed man had not committed a crime, but his presence was heightening tensions, so officers asked him to leave voluntarily. He eventually left with a police escort. No injuries were publicly reported in the confrontation between Mullen and the students, but the scene remained unsettled.
The protest did not end there. Chandler police said a white SUV tried to cross an intersection while a large group of demonstrators was moving through it, then pushed through the crowd and drove away. A motorcycle officer placed a police bike in front of traffic to stop other vehicles from entering the intersection. Investigators said they were still trying to identify the driver in the immediate aftermath. The department said it respected the right to peaceful assembly, while adding that reckless driving and throwing objects would not be tolerated. Those details placed the confrontation with the masked man inside a broader public-safety response that afternoon, with officers managing both crowd movement and sudden threats near students. The new identification of Mullen has brought renewed scrutiny to why an off-duty sergeant arrived armed at a school protest in the first place and why police records describe him as pushing the confrontation instead of stepping back from it.
That scrutiny widened this week as Phoenix officials and elected leaders reacted. Phoenix police said in a statement that the department was aware of the incident involving Mullen in a neighboring city and that the matter was under review by its Professional Standards Bureau. The department said he remains an employee. Mullen’s attorney said he had fully cooperated but would not comment further while the internal process continued. Phoenix City Councilmember Anna Hernandez, whose district includes the South Mountain precinct where Mullen works as a community action sergeant, said she raised concerns directly with Police Chief Matt Giordano. Hernandez said students were justified in fearing for their safety because no one at the protest knew the armed masked man was a Phoenix officer. Chandler Councilmember OD Harris also called for Mullen to be fired, saying trained law enforcement officers are supposed to de-escalate tense situations, not intensify them. Those comments added political pressure, but no public disciplinary decision had been announced by Thursday.
The reporting has also put new attention on Mullen’s standing inside city government. Court and employment records cited by local outlets said he has worked for Phoenix police since at least 2011. A review of city compensation data for 2025, as reported by FOX 10, placed him among the city’s highest-paid employees at more than $336,000 for the year. Those records do not decide whether his conduct violated department policy, but they help explain why the case has drawn such sharp reaction. He was not an unknown private citizen who wandered into a protest. He was an experienced supervisor in one of Arizona’s largest police departments, carrying an exposed handgun and extra magazines at a demonstration involving teenagers outside a high school. That background raises the stakes for the internal review because any finding will be read not only as a judgment on one officer, but as a signal about what standards Phoenix applies to senior personnel when they act off duty in politically charged settings.
On the legal side, the clearest public action so far has involved the juvenile case, not Mullen. The Maricopa County Attorney’s Office told ABC15 that the teenager arrested during the protest will not face charges. FOX 10 later reported that misdemeanor allegations submitted to juvenile court were declined for prosecution. That leaves the most visible legal consequence from Jan. 30 unresolved in a way that favors the student, even as the internal employment review of Mullen continues behind closed doors. Phoenix has not said when the Professional Standards Bureau will finish its work or whether its findings will be made public in full. Hernandez said she expects to be briefed, along with Mayor Kate Gallego, when the review is done. For now, the main unanswered questions are whether investigators find that Mullen violated policy, whether he faces discipline ranging from reprimand to termination, and whether Phoenix releases enough detail to explain how those decisions were reached.
The scene itself remains one of the most striking parts of the story because it blended youthful protest, fear and authority in a matter of minutes. Video from the event, along with accounts from a parent activist who recorded part of the confrontation, helped move the episode from a local disturbance into a wider debate over public trust. Students were protesting immigration enforcement, then found themselves facing an armed adult in a mask whose identity they did not know. Officers on scene decided he had not broken the law, yet they also described his presence as dangerous enough that they urged him to leave. That split is a large reason the case has continued to resonate. It captures a moment when something may have been lawful under Arizona’s gun rules, but still appeared deeply destabilizing in the context of a school protest. The public response since then suggests that many local officials view the case through that gap between legality and judgment.
The case stood Thursday with Mullen still on the job, the student case dropped and Phoenix’s internal investigation still underway. The next milestone is the Professional Standards Bureau’s finding, which city leaders say could be followed by a briefing from Chief Giordano.
Author note: Last updated April 9, 2026.