The Pontiac Fire Department Investigation Unit operates under the Support Services Division of the organization. All Pontiac Fire Department Investigators are certified by the Office of the State Fire Marshal of Illinois. The fire investigators are assigned by the Fire Chief to assist with determining the cause and origin of fires that occur within their jurisdiction. The Fire Investigator Unit also assist the Illinois State Fire Marshal's Fire Arson Investigators, as well as, Pontiac Police Department with investigating fires that are potentially associated with arson.
Currently, the Pontiac Fire Department Fire Investigation Unit is comprised of four members of the department. Capt. Joseph Hassinger oversees the unit that includes FF. Jeremy Highland, FF. Dillon Prendergast, and FF. Caleb Freese.