volunteer firefighter and leaves his two children, his wife. i feel bad. reporter: falkenhan s life is loss that will linger most in all of this but today work continues on this burnt-out shell. baltimore county fire called in the atm for assistance in what they call a full investigation. they look at all the physical clues as well as talking to people and they ll make every effort to determine where this fire began and how this fire began. reporter: fire investigators do believe there may have been a flashover or sudden burst in the fire that caused the brunt of the damage and in turn falkenhan s death. that is all part of the investigation, the clues of which are buried beneath the rubble in this burnt-out building. a seemingly pointless aside as firefighters and citizens alike mourn the loss of a man who, even in the end, put their lives in front of his own. he goes down as a hero in your book? yes, he does. he does. reporter: there were also two other civilian