One agency that is responsible for investigation and initiating prosecutions is the state fire marshal's office. Many members of these agencies throughout the various states have backgrounds firmly embedded in the fire service. But enforcing the law and complying with required procedures to acquire probable cause before taking action is also fundamental to their jobs. This makes their mission more law enforcement than it is fire service. Arson and arson-for-hire are felonies that cause millions of dollars in damage and injury each year, and often lives are lost as well. Investigations are tedious and technical, requiring an eye for detail, thoroughness, and an ability to function in very unpleasant environments. Fire scenes are dirty, smelly, dangerous places that demand a unique set of personal attributes in order to uncover the truth. Much of the physical evidence of the crime of arson is consumed in the fire, and this means that investigators must work with minute fragments of evidence and residuals in order to prove arson was committed.

Once the cause of a fire is established, and that cause is consistent with arson, the more difficult part of the investigation begins. Determining who the culprit is and acquiring sufficient evidence for an arrest and prosecution is a difficult and time-consuming task. It is for these reasons that the state fire marshal's office requires a special breed of law enforcement officer.