Question

1. You are investigating an arson scene and you find a corpse in the rubble, but you suspect that the victim did not die as a result of the fire. Instead, you suspect that the victim was murdered earlier and that the blaze was intentionally started to cover up the murder. How would you go about determining whether the victim died before the fire?

Answer 1

The measure carboxyhemoglobin (COHb) levels in the blood sample of deceased individual can be used as an effective tool for determining the actual cause of death. The normal level of COHb in the blood sample of a non-smoker individual is about 3% and for the smokers is around 10%.

​​​​Large amount of Carbon monoxide is produced during the fire. If the individual was alive and breathing at the time of an outbreak of fire, he must have inhaled a large quantity of Carbon monoxide. This would have highly elevated his COHb levels in the blood and caused death. However, if the individual had been already dead before the outbreak of fire, he would not be inhaling any air and thus no elevation would occur in the COHb levels in the blood of the deceased individual.

​​​​​The inhalation of Carbon monoxide during the outbreak of fire, causes very high elevation in COHb levels, both in the case of smokers and nonsmokers. The level of COHb, higher than 50% would be a good indicator to decide whether the death was caused by fire or not.

We can also check, if there are any burning marks present on the surface of throat and lungs of the deceased individual. This will be also be helpful in determining whether the person was breathing or already dead during the outbreak of fire.

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