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New details surface in Dusten Mullen investigation
We are uncovering more about an internal investigation into a Phoenix Police sergeant who has been placed on administrative leave in connection with an alleged off-duty incident during an anti-ICE protest. FOX 10 Investigator Justin Lum has more.
PHOENIX - We’re uncovering more about the internal investigation into a Phoenix police sergeant now on administrative leave amid ongoing controversy surrounding alleged off-duty misconduct during an anti-ICE protest involving students in Chandler.
The backstory:
We have been reporting on an incident involving Sgt. Dusten Mullen in recent days.
Per our first report on the incident on April 6, officials with the Chandler Police Department said a teenage girl was arrested on Jan. 30 outside Hamilton High School, and accused of throwing a water bottle at someone supporting ICE.
According to a report we obtained, however, a Chandler Police officer assigned to the protest said when a student pointed out a man with a full-face mask who seemed suspicious, he was seen walking back behind a palm tree. That man was later confirmed to be Mullen.
Dusten Mullen (right)
When the officer approached Mullen, he was arguing with students, telling them to "grow up and act like adults." He told the officer he wasn’t happy about kids flying flags that hit his car. The officer, however, says he never saw any flags touch the car.
The report states that students then became agitated, chanting and following Mullen, who they believed was an ICE agent. The Chandler officer advised him to take his protest elsewhere due to the volatile situation.
Dig deeper:
At the time of the incident, Mullen was armed with an exposed handgun in a holster and two extra handgun magazines.
Chandler Police’s report documents Mullen 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. I also have other people filming from a distance."
According to police, Mullen also said that more protesters in support of him were on the way, some armed with rifles, going on to say his goal was to "get all these kids in jail if they want to break the law."
We have learned it was Chandler Police, and not Mullen, who notified Phoenix Police about the alleged incident, another aspect under investigation by Phoenix Police's Professional standards Bureau.
On April 10, Phoenix Police Chief Matt Giordano said an employee with the department has been placed on administrative leave, following "a recent incident involving an off-duty officer in a neighboring city." The statement did not identify Mullen by name.
In the aftermath of Chief Giordano's announcement, an attorney representing Mullen said his client is being punished for protected speech, and called out the chief for implying that Mullen "engaged in misconduct."
The attorney, identified as Steve Serbalik, wants Chief Giordano to withdraw or correct his statement to the media, and lift the administrative leave.
New Details:
At the time of the incident, Mullen was a Community Action Sergeant, leading the Neighborhood Enforcement Team in the South Mountain precinct. Phoenix Police said Mullen completed mandatory First Amendment training and Public Safety Response Team training within the last six months, and his previous assignment gave him PSRT responsibilities during large incidents.
Meanwhile, city data shows that in 2025, Mullen made $336,000, meaning he ranked as the ninth-highest earner at the Phoenix Police Department.
"Is this standard for a sergeant of his ranking?" we asked Serbalik.
"It’s standard when people work overtime to be paid for the overtime that they’re working, and the Phoenix Police Department is experiencing a significant staffing issue," Serbalik replied.
Our recent interview with Serbalik also addressed Mullen's pay. According to family court records linked to Mullen’s divorce, a filing by his ex-wife in 2024 says he worked 60 to 80 hours a week.
Big picture view:
An audit released by the city of Phoenix in 2025 found that overtime costs skyrocketed 143% from July 2019 through the end of June 2024. The top 18 earners raked in more than $5.3 million in overtime alone between 2022 and April 2024. The audit also revealed Phoenix Police lacked effective oversight for overtime pay.
We asked Serbalik if Mullen’s hours were ever scrutinized as part of the audit.
"I can tell you that there has not been any discipline or investigation that I’m aware of [that are] related to the hours that Sergeant Mullen worked, because he was paid for the hours that he was working serving the community," Serbalik replied.
The Source: Information for this article was gathered by FOX 10 Investigator Justin Lum, as well as from previous FOX 10 news reports on the matter.