Arson is a fire which was caused deliberately, with malicious intent, to cover up another crime, or to collect insurance money on the property. As a crime, arson is taken very seriously because it puts property and human lives at risk. Most parts of the world have arson investigators, who inspect fire sites as a full time job. Usually, these investigators are licensed by the government of the area that they work in, and some work in tandem with insurance investigators, as the suspicious signs that both fire specialists are looking for tend to be the same.
Arson investigators are called out to the site of a suspicious fire to determine what exactly caused the fire, and if the fire was set intentionally. If the fire appears to be an arson, rather than an accident, the investigators will try to figure out where in the house the fire started and what was used to start it. Other law enforcement personnel will look into persons of interest in the case to see what their motives might have been and if they have solid alibis for the time that the fire occurred.
Trained arson investigators use a number of clues to investigate a fire, and are usually the first on the scene so that they can collect forensic evidence to examine from the site while it is still fresh. The first thing that they pinpoint is where the fire originated, because this is often a vital clue. Once the seat of the fire has been found, they can determine the cause: accelerants like flammable liquids, for example, or explosives. If an accelerant is detected, the fire is usually ruled an arson, as most people do not keep volatile liquids in the home because they are unsafe.
In addition to using their eyes, arson investigators heavily photograph the scene, so that if someone is brought to court, the jury can see pictures of the site. Also, the pictures sometimes reveal vital clues which were not spotted initially at the scene. The arson investigators frequently bring in dogs who are trained to look for signs of accelerants, and they take samples at the site for chemical analysis. Support staff investigate the samples brought back, and work together as a team to determine the cause of the fire.
If the fire is ruled not to be arson, arson investigators can still help the fire department figure out what happened. Common causes of fires include open flames, kitchen fires that get out of control, and faulty wiring. In some cases, the cause of the fire may not be covered under an insurance policy: if negligence was the cause, for example, the property owner may not receive compensation. For this reason, insurance fire investigators often inspect the scenes of non-suspicious fires to make sure that the fire is covered. Both specialists usually train together, because they have common goals as professionals.