Finally, some one got back to the intent of this thread. LOCKS! I should never have started this thread because as always, Pat & his girlfriend Steveareno, have to turn it into something that it is not. If every scene investigator used a system to investigate a fire, and used it the same way every time, no court will stop you from testifing to what you did if you do. You must make sure it conforms to all of the writen texts that are out there, including 921. If you determine that a fire it set and you can not tell your client or the court the condition of the security of the fire scene what good have you done for your client or your case? If you find the fire cause is accidental what have you lost checking the locks? Nothing, but you continue to gain experance. The time will come when the security of the structure will make the case. It's only one part of the fire scene but I have watched many State Fire Marshall's and other public investigators as well as private investigators not pay attention to the locks in a structure and who had the keys. You always run a risk of not being able to say a stranger broke in, we see that kind of scene everyday, but if you don't do it every time you are at a scene you are giving away to the dude who did the dirty deed.