Arson fires: three questions to understand how the investigation is carried out – France

For the two fires in the Monts d’Arrée, the Châteaulin Research Brigade is leading the investigation. More generally, in France, the Criminal Research Institute of the National Gendarmerie is called upon for laboratory analyses, in order to find the causes of a forest fire. He will be helped on the ground by foresters, firefighters and scientists.

In the South, another brigade investigates in addition. The research unit for the causes and circumstances of fires, created in 2003 following the major fires that affected the Var, has the role of interpreting the traces left by a fire.

Three steps are necessary to find the origin of a forest fire, according to the website of the Ministry of the Interior: the location of the hatching point, the demonstration of the hatching mechanism and the explanation of the spread of the fire in the forest.

If the technical causes (forestry work, clearing, etc.) and human causes (works, playgrounds, vehicles, etc.) have been ruled out, the investigators will consider the voluntary origin of the fire.

The research is then directed “towards the flammable products found on the scene”, indicates the Criminal Research Institute of the National Gendarmerie. “It can be a match, a delayed ignition device or, (…) by scratching the surface, an odor of hydrocarbons which emerges from the ground”.

If clues are found, samples are taken by criminal identification technicians (TIC).

If the fire is of voluntary origin, and therefore criminal, the arsonist faces up to 10 years in prison and a fine of 150,000 euros, according to the Service Public site. In the event of the death of a person, the penalty can go as far as criminal imprisonment, with the same fine.