Sometimes keeping it simple is the best way. That is why I am a fan of not saying the investigation was done following 921. I will explain my investigation as to how I collected the evidence from the scene, and how I evaluated this evidence. During the phase of the testimony, I will explain what I believe to be to origin of the fire. I then identify all the potential heat sources in the area of the origin. Then I go one by one over the different heat sources and explain how each was eliminated. This is the same method used in the scientific method when it comes to testing each hypothesis. I know this is the process of elimination that is not liked by many but is still a good method of explanation. Now, if none of the identifiable sources of heat can be connected to the ignition of the fire that is what I will say. Then the attorney will take me to what can ignite a fire if these items have been excluded. Of course, the answer is some type of human intervention. From that point we go into any opportunity for this to happen.

Because using this method is considered circumstantial evidence the level of proof that must be obtained in Louisiana is that assuming every fact to be proved that the evidence tends to prove, in order to convict, it must exclude every reasonable hypothesis of innocence. Almost sounds like the process of elimination.

I know each state is different, and it is important to know the requirements of your state. It is important for the investigator to know this information, so it is known what is needed to be successful. The trap the investigator does not want to get into is to state what is being said caused the fire may not be correct.

I have always preached, do not take the information in 921 as a fact. It is not wrong to use the information in 921 to assist in the investigation, but also make sure this information is correct. If you cannot verify the information, do not use it. This can be something as simple as the ignition temperature of wood as an example.

Jim Mazerat
Forensic Investigations Group