A fatal fire investigation involves determining the cause of the fire and the cause of the victim's death. The cause and manner of the victim's death will sometimes become a factor in deciding the nature of human involvement in the cause of the fire. The investigation shoud determine whether the victim was alive at the start of the fire, whether the victim ingested a substance that hindered his/her safe exit from the fire, and the victim's identity. If possible, the investigator should observe the body as it was found at the fire scene. Photographs should record the body's position at the scene, the body as debris is removed from it, the area on which the body was lying, and the underside of the body. The location, position, dress, and wounds of the body are important in determining the circumstances of the death. Interviews with witnesses circumstances of the death. Interviews with witnesses should focus on both the cause of the fire and the death. Those likely to have information in both these areas should be questioned. Evidence collected should contribute to determining the fire's cause, the victim's identity, and the instrumentality of death. Laboratory analysis and an autopsy of the victim are important tools for evidence examination. The final report should present reasons for the final conclusion of the investigation.