FLAGSTAFF, Ariz. – On Monday, August 29, 2025, Flagstaff Medical Center (FMC) received alarming emails that suggested the possibility of an active attacker situation. Hospital security immediately contacted the Flagstaff Police Department (FPD), launching a criminal investigation.
Through the investigation, officers identified Tristan Long, 23, as a suspect. Long had recently applied for employment at FMC, and staff suspected him of sending the threatening messages.
Given the seriousness of the threats and the risk to staff and patients, Long’s vehicle was entered into the Flock Safety Automatic License Plate Reader (ALPR) system. His vehicle was last observed leaving the city, and law enforcement placed it on a “hot list,” ensuring officers would be alerted if it reentered Flagstaff.
On September 5, 2025, the system detected Long’s vehicle traveling back into the city. FPD officers quickly located the car using the ALPR network and safely took Long into custody without incident.
A search of his vehicle uncovered a loaded rifle magazine and several boxes of ammunition. Long was transported to FPD headquarters for questioning before being booked into the Coconino County Jail on charges of threatening and intimidating.
Authorities emphasized that the ALPR technology played a critical role in ensuring public safety and preventing potential violence.
The investigation remains active. Anyone with information is urged to contact the Flagstaff Police Department at (928) 774-1414 or Silent Witness at (928) 774-6111.
