Destroying the evidence...

The court case I sat through earlier this month is now reaching a conclusion. It has been extremely interesting as it involves a double killing and the victims’ bodies were destroyed in a very efficient manner in what is perhaps best described as a ‘homemade’ crematorium. The Bundeskriminalamt’s Forensic Experts have been involved by the defence team as the court had been advised that it was not possible to destroy a body, let alone two, in the manner described. However, the BKA team has shown that it is possible since the key element is not, as the original expert asserted, the temperatures generated or the method, but the combination of temperature and duration.

The court had a further difficulty in that the original investigation did not attempt to reconstruct the cremation equipment which the accused had, by that time, destroyed. Nor did they examine fully the information provided. Some ‘semantics’ were also involved which further clouded the issue, the accused stating that “the bodies were totally destroyed.” The use of the word “totally” was seized upon by the original expert as being “impossible”, but it is now accepted that this interpretation is far too narrow, since, to a layman, “totally destroyed” means being unable to recognise anything in the debris that he/she could identify as human.

So, how was this done?

The accused provided a detailed description of what he had done and how. When this methodology was examined fully and the implications studied and heat fluxes calculated it was found that the accused could well have destroyed the bodies sufficiently for the remains to be unrecognisable. His first step was to create a furnace.

To do this he cut the top off a small LPG ‘Bullet’ tank. This normally stands about 1.7 meters in height and has a diameter of 1.5 meters with a length of around 4 metres. Cutting the top off the tank reduced the height to 1.4 metres, allowing the fire bed to be fed from above. Slots approximately 100mm in length and 40mm in width were cut around the lower part of the tank, roughly 3-400 mm from the bottom. A fire was made inside the tank using wooden pallets and sustained until there was a deep bed of coals. More timber was then added to this and the first body, now wrapped in a poly-butylene “Butyl Rubber” pool lining sheet and placed inside a purpose made wooden ‘coffin’ was suspended over the top opening in the tank (This was 1 metre in width and the ‘coffin 900mm) and the fire using a mobile hoist. The Polypropylene strops melted and allowed the box to drop into the tank where the butyl sheet liquefied and promoted the rapid burning of the box.

Once the first box had begun to burn the second box was placed on top of it and caused the first to collapse, lowering the second completely into the tank.
Over the next eighteen hours the accused continued to stoke the fire, feeding in broken pallets from the top. This was one of the ‘issues’ the court had with the testimony since they believed the top would be too high for the accused to do this or to see into the tank unless he stood above the tank on an adjoining wall. However, this is where the original investigation was misleading. No one had drawn a scale drawing from the accused’s and other witnesses accounts. Once the BKA drawing was presented, complete with a to scale human figure, it immediately became obvious that not only was it possible to feed the fire as described, but to see into the tank without undue exposure to the heat or flames.

For me this underscored the need for investigators to make accurate scale drawings of anything they may need to look at in more detail or to verify witness descriptions. It certainly rocked the court’s perception and changed the opinion of the bench and assessors completely.

The calculations produced for the heat generated and output of a fire in these conditions were extremely complex, but showed that the burning pallet material would have produced sufficient heat to reduce a body and almost all the major bones to ash. When combined with the Butyl Rubber sheeting and the body’s own fatty tissues, the heat generated over the period of time given (18 hours) would have reduced the remains to fragments unrecognisable by any lay person. The BKA expert advised the court, and was supported in this by the Pathologist, that any larger pieces remaining would be sufficiently friable to be reduced to powder very simply either by handling or by the application of an acetylene torch on the premises. The accused’s reaction to this was sufficient to confirm suspicions that this is indeed what happened and he confirmed that verbally to the open court!

The calculations for radiant heat from the tank also confirmed that anyone ‘feeding the fire’ would be able to do so with only slight heat discomfort at a distance no more than 500 mm from the tank wall.

One of the many things that has caused a problem with this case is the fact that, though the accused showed the police where he had scattered the remains in a field, no attempt was made at the time to collect any samples from it or from the area where the tank had stood. Had this been done, the BKS team could have analysed it using X-Ray diffraction, a technique that reveals the crystalline structures off a variety of chemicals and would have shown up the Calcium Phosphates unique to human bones…

Sitting in on this case has been a fascinating learning experience, not least for the scientific analysis of the process, but for the identification of the many deficiencies in the original investigation. The court is to sit again on the 1st of August to hear a statement by a co-accused and the judgement will follow, I suspect, within days of that. It certainly bears out, for me, the vital necessity for fire investigators to understand the recording, recreation and evidence examination techniques as well as the fire!

Hopefully, at some point I will be able to post the drawings and some of the calculations on this site – but for the moment this is verboten!