Wednesday, 12 January 2011

Cadaver scent, proof of death or the walking dead?.

Goncalo Amaral hung his hat on a thesis that could only make sense if there were positive forensic results from the dog alerts. The issue of these alerts have resulted in some people believing that the scent being alerted to automatically means that decomposing matter from a dead person, or persons, has been found. To believe that alerting to the scent, for which the dog has been trained, means finding a decomposing body when there is very minute quantities of alerting substance, is very foolish indeed, especially when that belief is being considered as proof positive. Without a complimenting physical find beyond the dog alerts, the question of what the dogs found opens up the possibility that the scent alerted to, could be sourced from the blood lost by a live human being as well as scent contamination from a number of sources that could undermine any value in validity as conclusive evidence pointing specifically to a suspected dead human under investigation. The matter found has only one possible avenue of interpretation to indicate what the scent is, that of forensic testing. In this case we know that the forensic results could not show any confirmation that Madeleine was found in the DNA and could not determine the source of the cadaver scent.

Eddie the EVRD (Enhanced Victim Recovery Dog), cadaver dog, alerted to the scent of which he is trained to find. Let’s look at the possible sources of that scent, knowing that the results do not confirm the source being Madeleine, it is important to explore what the source of the scent could be, considering the absence of conclusive proof of the known missing person in the chemical brew, being dead or alive.

Eddie was trained using pig meat in the UK as the use of decomposing human beings is not accepted in the UK as yet to train these dogs. However, Eddie did undergo training in the USA using decomposing human beings. The olfactory system of a dog is considered hundreds of times stronger than the sense of smell for a human being. Yet it is not fully understood what components of a decomposing human body are sensed by an alerting dog, to give an alert to cadaver scent. On further investigation I have made some interesting findings regarding volatile cadaver chemical components which are found in living human beings.

Dried blood from a living human.

Martin Grime, Eddie and Keela's trainer and handler, confirms in his rogatory interview, on the subject specifically about the Cadaver Dog, that Eddie can alert to dried blood from a living person.

"The dog EVRD (Eddie the Cadaver dog) is trained using whole and disintegrated material, blood, bone tissue, teeth, etc. and decomposed cross-contaminants. The dog will recognize all or parts of a human cadaver. He is not trained for 'live' human odours; no trained dog will recognize the smell of 'fresh blood'. They find, however, and give the alert for dried blood from a live human being."

Cadaverine from a living human.

Cadaverine is the decarboxylation product of the amino acid lysine. However, this diamine is not purely associated with putrefaction. It is also produced in small quantities by living beings. It is partially responsible for the distinctive odours of urine and semen. Elevated levels of cadaverine have been found in the urine of some patients with defects in lysine metabolism.

Putrescence from a living human.

Putrescine (sometimes spelled putrescin) is a foul-smelling organic chemical compound NH2(CH2)4NH2 (1,4-diaminobutane or butanediamine) that is related to cadaverine; both are produced by the breakdown of amino acids in living and dead organisms and both are toxic in large doses. The two compounds are largely responsible for the foul odour of putrefying flesh, but also contribute to the odour of such processes as bad breath and bacterial vaginosis. They are also found in semen and some microalgae, together with related molecules like spermine and spermidine. 

Bad breath, malodor and periodontal disease

Several tests were done by scientists to determine the association of Cadaverine and Putrecine in humans with complaints resulting in bad breath.

Researchers Goldberg, Kozlovsky, and Rosenberg designed a study to evaluate the contribution of diamines (especially cadaverine and putrescine) to bad breath. They studied 52 people, most of whom complained of bad breath. The researchers measured:
  • the VSC with a portable sulfide monitor, 
  • mouth odor via organoleptic means,
  • plaque index,
  • gingival index, 
  • probing depths, 
  • BANA test results, and
  • levels of cadaverine and putrescine in the saliva.
Results of the study included:
 Cadaverine scores were associated with odour judge organoleptic scores, plaque index scores, and gingival index scores. Cadaverine levels were also relative to the BANA scores and mean probing depth. Cadaverine levels were not associated with VSC levels.
 Putrescine levels were not significantly related to the malodor and periodontal measurements, but were related to cadaverine levels.
 In a second experiment, they compared saliva from a patient with periodontal disease to saliva from a patient who had healthy gingiva. The sample from the periodontitis patient had higher cadaverine levels. Putrescine levels in both samples were similar.
The results of this study showed cadaverine levels are associated with malodor and periodontal disease, while putrescine's role is still somewhat unknown. 

I don’t purport to be an expert in forensic science, but I have become an expert in researching the subject and the relation to cadaver dogs, specifically in the situation the case of missing Madeleine has presented us. I have spoken to experts and researched scientific data, have listened to those who believe cadaver dog alerts must only mean death alerts and have questioned myself.

My conclusion is that with such low amounts of matter available to view as evidence, forensic science had to interperate what the dogs alerted to. That interpretation showed that the alerts could not determine information for use as proof of a death, contamination from dead bodies or of Madeleine’s death. In fact, the alerts can be innocently explained away with the inclusive factor that the scent could very well be from saliva, dried blood and other bodily fluids from living humans. The EVRD dog is not trained to detect live humans, but the inconclusive result, from the forensic scientists, is proof that there is hope for Madeleine being found alive and that there is hope one day Goncalo Amaral will decide to face the fact that he built his 'house of cards' thesis upon only one card.

By Deuce