I recently had a discussion with a PI from another state than mine who says that a fire investigation begins only when the fire investigator steps foot on the fire scene itself. I disagreed. What is yall take on this subject when do you think your fire investigation begins or starts and while NFPA 921 Sci Meathod says to collect date ( doesnt say fire scene ) is there anywhere else off the top of you head such as ASTM or other referance material that speaks to this matter.