Far be it for me to start another canine thread but there are some issues which must be clarified. In doing so I hope to have the question answered, are Victim Detection and Forensic Evidence Search Dogs reliable?
The 'dogs' received some almighty bad Press back in 2007 as a consequence of two extremely high profile cases, namely, the disappearance of Madeleine McCann followed soon after by the Jersey Child Abuse Probe. The dogs also attracted further criticism in 2008 following the kidnapping of Shannon Matthews.
Police handler Martin Grime with Enhanced Victim Recovery Dog Eddie.
I don't intend to delve into these cases in my introduction except to explain to anyone who doesn't already know that in the McCann case no evidence of remains were ever found despite several alerts and in the Jersey probe all that was found were milk teeth and a piece of coconut shell together with some ancient bones. In the Matthews case, the child was later found safe and well despite alerts by several dogs. The reason for this being given that second-hand furniture brought into the family home had previously been contaminated by death scent from an unconnected source.
A piece of cocunut shell wrongly identified as a fragment of child's skull during the Jersey probe.
Further information on the cases referred to above can be found within the forum, alternatively refer to the following links...
> Jersey child abuse probe.
> Disappearance of Madeleine McCann.
> More than half UK's sniffer dogs involved in search for Shannon Matthews.
Are cadaver dogs useful?
They
can be immensely useful in either of two ways: they can find cadavers and (as an introduced training extra to enhance their usefulness) they can detect blood, which can be captured and analysed in a laboratory for DNA information, which can identify suspects or victims.
It is for that reason that cadaver dogs are trained to detect blood.
An obvious drawback of training a dog to react to blood is that, the wider the range of substance (or, more accurately, scents emitting from those substances) a dog will react to, the greater the chance of an alert, not necessarily false (as it may be within the dog's training parameters) but just not helpful to an enquiry.
That is why
some States of America (not all) permit use of human remains and human body parts to train dogs.
Those US States that do not, and all the rest of the world where cadaver dogs are trained and employed, use swine cadavers and (very often) pseudo-scents as the basis of their training.
A primary constituent of pseudo-scents is cadaverine, which can also be present in people or by-products of people who are alive.
That is a limitation on the usefulness of cadaver dogs. Decayed products lost by
living people may trigger a reaction, which is within a dogs' trained parameters, but just may not be relevant to the criminal enquiry at hand.
The other (possible) limitation on the use of dogs is bias. The Portuguese handlers certainly understood about bias. The handlers were not told which apartment Madeleine had been living in so that they would not become (sic)
conditioned.
I believe the whole basis of the US
forensic canine program is to limit the cadaver dog to strictly human cadaver scent (
not blood) in a bid to increase assurance of the accuracy of a cadaver-dog alert. If you can limit or (better still) eliminate the range of extraneous (to a human cadaver) scents a dog might be likely to react to, you can have greater confidence that the dog has scented a death scent, even where physical evidence of the alert is not recovered.
And if you have a specialist blood dog to be deployed separately, neither do you lose the advantage of finding blood, if it there is blood to be found.
So in summary, a cadaver dog
can be of immense benefit to a criminal enquiry.
Or it can confound a criminal enquiry by alerting to scents, within its trained range, but just not relevant to the enquiry at hand.
And finally, handler-bias can impair the accuracy and reliability of a dogs' reactions or alerts.
