Using the Scientific Method as outlined in 921 I would say my investigation starts when I recognize the need for an investigation. For the public sector this can be at the time of the call out, where with the private sector it could be at the time of an email, telephone call or some other communication requesting you conduct an investigation. Once you accept the call out or agree to conduct an investigation you have now determined that a fire or explosion has taken place and there is a need to determine the cause.

Jim Mazerat
Forensic Investigations Group