THE IMPORTANCE OF LEAVING ANY BODIES AT THE FIRE SCENE UNTIL INVESTIGATORS ARRIVE IS STRESSED. THE FIRE INVESTIGATOR AND PATHOLOGIST CAN OBTAIN IMPORTANT INFORMATION FROM THE POSITION, CONDITION, AND LOCATION OF THE BODY. THEY MUST DETERMINE WHETHER THE VICTIM WAS ALIVE OR DEAD BEFORE THE BEGINNING OF THE FIRE. FIRST THE FIRE INVESTIGATOR DETERMINES THE SOURCE OF THE FIRE AND ITS POINT OF ORIGIN. TO DO SO, HE MUST HAVE A KNOWLEDGE OF THE PHYSICS OF A FIRE, ITS DEVELOPMENT, AND HOW IT SPREADS. SOURCES SUCH AS SPONTANEOUS IGNITION, LIGHTNING, AND HUMAN CARELESSNESS MUST BE ELIMINATED BEFORE HE BECOMES SUSPICIOUS OF THE FIRE'S ORIGINS. IT IS EASILY DETERMINED IF A CHILD CAUSED THE FIRE FROM EVIDENCE LEFT LYING AROUND; EXPLOSIONS ARE ALSO OBVIOUS. IN MOST CASES INVESTIGATORS RELY ON THE CIRCUMSTANTIAL EVIDENCE AT THE SCENE. IT IS RECOMMENDED THAT AN AUTOPSY ALWAYS BE PERFORMED UPON FIRE VICTIMS, PARTICULARLY IF THE FIRE'S SOURCE IS SUSPICIOUS. THE INVESTIGATOR SHOULD ALSO TAKE A COMPLETE SET OF PHOTOGRAPHS OF THE SCENE, HAVE THE BODY IDENTIFIED BY THE PATHOLOGIST, AND TAKE GREAT CARE TO PRESERVE THE FIRE SCENE EXACTLY AS IT WAS FOUND. COMMON MOTIVES FOR ARSON ARE OUTLINED. THESE INCLUDE PYROMANIA, REVENGE, INSURANCE FRAUD, INTOXICATION, AND COVERING UP A CRIME. (VDA)