the building. does that tell you anything? >> well, the way they get to that point is to go by burn patterns. first they look at an area that's burned the least and work their way to the area burned the most. the area of origin is a general area and that's what they were speaking to, an area of origin. they are subsequently going to try to refine that down to a point of origin. once you determine the point of origin, they would then go through a process of eliminating various causes to determine the cause of the fire. >> this is going to be so difficult for them, because the building is unstable. in fact, they stopped searching for bodies because it's just too dangerous for fire officials right now. >> yes. the issue is you have to have safety for the investigators. otherwise, you will have more casualties among the fire investigators.