An origin and cause investigation is an investigation into the circumstances of a fire. The goal of the investigation is to determine where and how the fire originated, to figure out whether it is arson or not, and to provide clues into who might be responsible for the fire. You may also hear origin and cause investigation referred to simply as an arson or fire investigation.
In most regions of the world, in order to practice this branch of forensics, an individual or company must be licensed. To receive licensing, people have to demonstrate the ability to investigate fires accurately and safely. Training in arson investigation typically involves learning about how fires work, what causes fires, how emergency services personnel handle the scene of the fire, and how to collect evidence. Because evidence from the fire can be used in a court of law in the event of an arson, it is important to maintain the integrity of evidence.
Origin and cause investigation is an interesting branch of forensics, because one of the goals is to determine whether or not a crime has been committed. In most cases, forensics involves the study of a specific crime, like a murder or kidnapping, in order to collect clues to help solve it. Fire investigators have to start out by finding out what happened before they can move on to the “who” of the fire.
In a typical origin and cause investigation, investigators arrive on scene at a fire as quickly as possible to collect evidence, sometimes showing up while the fire is still burning to see if any patterns can be detected. Some fire departments are licensed to carry out such investigations, and in other cases a private company or government agency will be used. As soon as a fire department clears the site, indicating that it is safe to work in, investigators move in. They examine the site meticulously, taking lots of photographs to document their work and taking samples of interest.
Samples are analyzed in a laboratory setting for evidence such as traces of an accelerant, an agent which could have increased the intensity of the fire. Origin and cause investigators try to figure out where the fire started, and what caused it: a loose electrical connection, for example, or a can of gasoline and a match. The crew may use arson dogs to search for traces of accelerants, along with cadaver dogs to look for signs of victims.
Sometimes, the results of an origin and cause investigation are inconclusive. The investigators may not be able to determine whether the fire was accidental or not, ruling the fire “suspicious” but not a definite arson. The investigation may also reveal that the fire was an arson, but provide no clues as to who was responsible; further investigation can become a job for law enforcement or insurance companies.