Mesa Firefighter Mark Keller Dies Suddenly While On Duty — Department and Community Mourn Beloved Veteran Paramedic

MESA, Ariz. — The Mesa Fire and Medical Department is in mourning following the sudden death of Firefighter Paramedic Mark Keller, who passed away while on duty early Tuesday, May 6, 2025. Keller, a 35-year veteran of the department, was found unresponsive at his fire station and later pronounced deceased.

Fire Chief Mary Cameli issued a heartfelt statement Tuesday morning:

“It is with a heavy heart that I share that our department lost Firefighter Paramedic Mark Keller while he was on duty. Mark was not just a colleague but a friend and a pillar of strength in this department for over three decades. Our thoughts are with his family, his crew, and all who had the honor of working alongside him.”

Mark Keller began his career with the Mesa Fire and Medical Department in 1990. Over the years, he earned a reputation for compassion, professionalism, and unwavering service to the community. Colleagues described him as someone who always placed others before himself, both on the job and off.

Mesa Mayor Mark Freeman, a retired Mesa Fire Captain who once served alongside Keller, also shared a tribute:

“Mark was not only a trusted colleague but a true friend. I had the privilege of working with him closely throughout my career, and I saw firsthand his commitment to our city and its residents. His passing is an immeasurable loss. Our city grieves with the Keller family.”

The cause of Keller’s death has not been publicly released. His body was transported in a solemn procession to the Maricopa County Office of the Medical Examiner. First responders from multiple agencies, including the Maricopa County Sheriff’s Office, joined in honoring Keller during the transport.

Support services, including fire chaplains, peer counselors, and union representatives from United Mesa Firefighters Local 2260, have been mobilized to assist Keller’s family and fellow firefighters during this difficult time.

The community response has been swift and heartfelt. Residents have taken to social media to share memories and messages of condolence. One woman recalled Keller arriving during a medical emergency involving her father:

“He was so kind, so calm — a true professional. I will never forget his compassion. He made a difference in our lives that day.”

As the city of Mesa comes to terms with the loss, plans for a public memorial are expected to be announced in the coming days.

Firefighter Mark Keller’s legacy is one of service, sacrifice, and enduring impact. He is survived by family, friends, and an entire fire department family who will remember him not only for his work — but for the kind of person he was.

Rest in peace, Firefighter Paramedic Mark Keller. Your service will never be forgotten.