Fire Investigations are the responsibility of the Princeton Fire Marshal's Office for investigating fires within the City of Princeton. Fire investigators are certified Texas peace officers through the Texas Commission on Law Enforcement (TCOLE). Investigators a all Texas Commission on Fire protection certified fire fighters. Along with holding a Peace Officer Commission, investigators have to be certified by the Texas Commission on Fire Protection (TCFP) as Arson Investigators. Investigators must attend regular training in order to maintain certification and be up to date on the most advanced methods of fire investigation.
The Princeton Fire Marshal's Office maintains a close working relationship with other fire and arson investigating agencies.
The Princeton Fire Marshal's Office treats every fire scene as a possible crime scene in order to properly preserve any evidence of what may have been the cause. A fire scene is investigated from the area of least damage working backwards towards the area of the most severe damage. In some cases, the cause of the fire may be accidental due to faulty electrical wiring, overloaded electrical systems, candles, smoking materials such as cigarettes, faulty motors, cooking fires, or any other type of accidental fires. Some fires are natural, caused by decomposition of materials (a compost pile), lightning, or spontaneous combustion of some chemicals.
In other cases, the fire may be incendiary (arson), meaning that the fire was intentionally started. Some common motives for setting intentional fires are for profit (insurance fraud), revenge, and concealment of another crime (such as a home invasion, drug house, homicide, vehicle used in a robbery), vandalism, excitement, and extremism (extremist groups setting fires in order to further their cause). When a fire is determined to be arson, the Princeton Fire Marshal's Office conduct a full criminal investigation aggressively pursuing those individuals responsible and execute arrest warrants, search warrants, and refer cases for prosecution with the Colin County criminal district attorney.