Christopher’s autopsy results show that he inhaled smoke, indicating that he was alive and upstairs at the time the fire started. This makes the prosecution’s case impossible but it is entirely consistent with Jeff’s account of what happened.
About Carbon Monoxide
Carbon monoxide (CO) is a colourless, odourless gas that is produced when things burn. All fires produce CO. Other sources of CO include car engines and cigarette smoke.
Forensic pathologists and toxicologists routinely test the levels of CO in the blood of fire victims to determine whether a person was alive or dead before the fire started.
Everyone has a small amount of CO in their blood. According to scientific literature, non-smokers have a normal level of CO between 0.4 and 1.4%. Due to their regular contact with smoke, smokers may have up to 9% CO in their blood.
No one in the Gilham house smoked cigarettes. Helen, Stephen and Christopher were non-smokers. If they had died before the fire started, it would be expected that their CO level would be somewhere between 0.4 – 1.4%.
- Helen Gilham’s blood CO level was 3%,
- Stephen’s level was 4%
- Christopher’s CO level was 6% – over four times the upper limit of normal.
This result shows that Christopher inhaled smoke prior to his death.
Why does this matter?
The prosecution claimed that Christopher was killed on the downstairs level of the house (away from any smoke or fire) at least 15 minutes before the fire started. The prosecution argued that in that time, after Jeff had killed his entire family, he then set out to do a number of things, such as washing, attempting to syphon petrol and distributing mineral turpentine to accelerate the fire, before he sought the help of a neighbour.
By taking this approach, the prosecution tried to deal with a key weakness in the case against Jeff: Why Christopher, staying just downstairs from his parents, did nothing to assist his parents even when their screams could be heard by neighbours over 50 meters away.
This evidence confirms that Christopher was not dead or dying while the fire took hold upstairs. It shows instead that he was alive and upstairs breathing in the smoke from the fire.
The level of CO in Christopher’s bloodstream is entirely consistent with Jeff’s account of discovering Christopher upstairs and seeing Christopher start the fire.
How this was Presented to the Jury
The prosecutor’s expert witness described each of the CO results as negative, indicating that all three were dead at the time of the fire. He said:
“In the normal course of things in looking at a person with stab wounds and fire damage, a level of less than 10 per cent would be assumed to be that the person had died before the fire started.”
The jury were told the level was not significant — it meant nothing.
This is simply not correct given that scientific literature has long-established background levels of CO in non-smokers.
Christopher was a non-smoker, his body had no fire damage and he died well away from any fire or smoke, and hence his blood CO level was consistent with him being alive for a period of time after the fire was started.