Les chiens sont déployés comme des instruments de recherche afin d'obtenir des preuves et de localiser des restes humains ou du sang humain.Les chiens ne sont pas venus de Grande-Bretagne pour chercher une enfant enlevée mais pour chercher des preuves de sa mort, accidentelle ou non. Ils ont alerté à plusieurs endroits. Aucune corroboration forensique n'a pu être mise au jour. Il n'en demeure pas moins que les alertes des chiens doivent être prises en compte à titre d'indications.
Au moment de la mort, l'odeur émise par le corps humain subit une transformation. L'odeur de la décomposition se forme peu à peu et au bout d'un certain temps elle devient plus forte que celle du corps avant la mort. Les hommes mettent plus longtemps que les chiens à détecter l'odeur de cadavre. Le corps traverse cinq stades de décomposition avant d'être squelettisé et les chiens sont dressés à réagir à l'éventail des odeurs présentes à chaque stade.
Il n'y a pas (encore) de procédés
ou d'équipement de laboratoire aussi sensibles que le système
olfactif du chien. L'instinct de chasse naturel du chien et sa capacité à détecter des odeurs ne peut être mise en échec.
À la différence des hommes qui ne se plaisent à sentir que l'odeur agréable d'un gâteau qui vient de sortir du four, le chien est capable de distinguer l'odeur de chaque ingrédient individuel de la recette, simplement en sentant le gâteau. Il peut localiser l'odeur même si celle-ci est mélangée à d'autres.
Quand un être meurt, la décomposition commence immédiatement, la synthèse des protéines s'arrête. Si rien ne maintient l'enveloppe de protection de
l'estomac, les enzymes digèrent le corps de l'intérieur et produisent des acides aminés. Des bactéries s'en nourrissent.
Les chiens spécialement dressés pour trouver des cadavres ou des restes humains, y compris les odeurs résiduelles après le déplacement d'un cadavre, sont appelés "détecteurs de restes humains". Ces chiens son§t
capables de découvrir l'odeur d'un cadavre alors qu'il n'y a plus de
preuve physique visible ou palpable.
Après la mort, les COV provenant des gaz produits par la décomposition, des cellules de desquamation de la peau, des débris volatiles, celulaires et bactériens enveloppant le corps se répandent dans l'air ambiant et se fixent sur certains supports (adsorption).
Des expériences ont
montré que l'odeur résiduelle d'un cadavre humain peut rester un an
dans un bâtiment sans grande perturbation humaine ou
environnementale, alors donc que la source directe des COV ait été enlevée (dans l'expérience d'Adela Morris, une compresse placée sur un cadavre pendant un certain temps et conservée ensuite à l'abri de l'air).
1
Détection canine de cadavre et de sang humains
Texte original, en anglais, rédigé par MG
Licensing and accreditation
U.K.,
A.C.P.O. licensed and accredited cadaver dogs are trained and licensed
on the basis of the relevant section of the Police Dog Training and Care
manual. This involves the training of G.P. (General Purpose) dogs to
alert to the presence of surface deposition and sub-surface deposition
to approximately 2 feet. The dogs are deployed on long lines to search
an area in large numbers.
The
U.K. has also approximately six Police dog teams that have been trained
exclusively on decomposing pig remains not for human consumption as
specialist dogs to work off the leash to locate human remains in a wider
variety of scenarios. Pig is used as it has been proven in training and
operationally over the last 20 years to be a reliable analogue for
human remains detecting training for dogs. The possession of human
remains for the purpose of training dogs in the U.K. is not acceptable
at this point in time.
Licensing
is derived from anecdotal cases and is scenario based conducted over a
period of a week, twice annually, it is conducted utilising independent
A.C.P.O. authorised assessors. Continuation training is conducted on a
daily basis and includes simple scent discrimination testing to large
scale scenario based exercises.
Both
dogs and I are licensed as two separate working teams. We are
independently tested and licensed annually, normally at six monthly
intervals as a 'rolling' programme to ensure best practice is
maintained. They are tested to units of assessment prepared as a
stand-alone system as these dogs are unique. Training records are
maintained and are available if required.
All operational deployments are video recorded including a control sample find when appropriate.
Présentation
Présentation
I am an U.K.A.C.P.O.
accredited police dog training instructor in post at the Operational
Support Services. I am a Subject Matter Expert registered with
N.C.P.E. and specialist homicide canine search advisor. In support of
the national Homicide Search Advisor, Mark Harrison, I advise
Domestic and International Law enforcement agencies on the
operational deployment of Police Dogs in the role of Homicide
investigation. I develop methods of detecting forensically
recoverable evidence by the use of dogs and facilitate training.
I am a Special Advisor to
The U.S. Department of Justice, Federal Bureau of Investigation, in
relation to their Canine Forensic Program. I am regularly deployed to
assist in high profile homicide cases within my portfolio and form a
'Specialist Canine Homicide Search Team' including the S.A.M dog
teams from Dyfed Powys.
My core role includes the
training and operational handling of specialist search dogs in the
fields of Human Victim Recovery and Forensic Crime Scene
Investigation.
I have trained and handle
two operational specialist search dogs. 'Eddie' is a 7-yearold
English Springer spaniel dog. 'Keela' is a three-year old English
Springer spaniel bitch. I also have a six-month old English Springer
spaniel dog, puppy, in training, 'Morse' .
Training and Cadaver scent
The
dog, a scavenger, uses its olfactory system to locate food sources,
identify its young, other pack members, enemies and predators over large
distances. It can track its prey identifying a direction of travel.
This entails the dog being able to discriminate the time difference
between footsteps using the sense of smell. The reward of food and
protection / close comfort provides the basis for a system to be adopted
where the dog shows a willingness to respond in response to the reward.
We are thereby able to 'train' the dog using conditioned responses to
stimuli. Repetition and reward then ensure efficiency. Positive and
negative reinforcement then shape the required behaviour in their role.
Within the role of these dogs they are utilising basis survival instinct
but have undergone behaviour shaping to alert the handler to their
finding as opposed to consummation. Pavlov's theory is used in the case
of the E.V.R.D. system of alert. He has been 'conditioned' to give a
verbal alert when coming into contact with 'dead body scent'. The
presence of tangible material is not required to produce the response
merely the scent itself. Pseudo scent is an artificially chemically
produced product that its manufacturers
claim to resemble 'dead body scent'. Although some cadaver dog trainers
have had limited success with its use in training, when tested on my
dogs they showed no interest and it is not used as a training aid for
them.
Tous les chiens policiers britanniques, quelque soit leur domaine de compétence, doivent avoir une licence pour participer à des interventions opérationnelles. Pour obtenir cette licence, ils doivent passer un test à la fin de l'entraînement et ensuite repasser un test tous les ans. Les critères requis sont établis par un comité de l'association des officiers de police et sont révisés régulièrement afin d'assurer que le dressage reflète les méthodes et critères les plus appropriés.
Le dressage et le travail opérationnel sont enregistrés et les enregistrements peuvent être utilisés dans les instructions en tant que témoignant de la fiabilité du tandem maître chien/chien et dans la mesure où les résultats obtenus témoignent de leur compétence.
In
my role as advisor to the U.S. Justice Department I have facilitated
assessment of numerous cadaver search dog teams in the United States.
These dogs are exclusively trained using human cadaver sources. When I
introduced decomposing pig cadavers into training assessments 100 % of
the animals alerted to the medium. (The products were obtained from
whole piglet cadaver not processed food for human consumption). The
result from scientific experiments and research to date is suggestive
that the scent of human
and pig decomposing material is so similar that we are unable to
'train' the dog to distinguish between the two. That is not to say that
this may not be possible in the future.
Et pourtant des recherches ont montré que les empreintes olfactives du cochon et de l'homme ne sont pas très proches.
The
odour target of cadaver is scientifically explained through 'volatile
organic compounds' that in a certain configuration are received by the
dog as a receptor. Recognition then gives a conditioned response
'ALERT'. Despite considerable research and analytical investigation the
compounds cannot as yet be replicated in laboratory processes. Therefore
the 'alert' by dogs without a tangible source cannot be forensically
proven at this time. Cadaver scent cannot readily be removed by cleaning
as the compounds adhere to surfaces.
The
scent can be 'masked' by bleach and other strong smelling odours but
the dog's olfactory system is able to isolate the odours and identify
specific compounds' and mixes. Cadaver scent contamination may be
transferred in numerous scenarios. Any contact with a cadaver which is
then passed to any other material may be recognised by the dog causing a
'trigger' indication.
EVRD
'Eddie' The Enhanced Victim Recovery Dog (E.V.R.D.) will search for and locate human remains and body fluids including blood in any environment or terrain. The initial training of the dog was conducted using human blood and still born decomposing piglets. The use of human remains for the purpose of training dogs in the U.K. is not acceptable at this point in time. The importance of this is that the dog is introduced to the scent of a decomposing body NOT FOODSTUFF. This ensures that the dog disregards the 'bacon sandwich' and 'kebab' etc that is ever present in the background environment. Therefore the dog would remain efficient searching for a cadaver in a café where the clientele were sat eating bacon sandwiches. He has additionally trained exclusively using human remains in the U.S.A. in association with the F.B.I. En 2005 Eddie (et Keela) ont "fait un stage" dans la première body farm états-unienne qui dépend de l'université du Tennessee et où se trouvent des cadavres dans de multiples stades de décomposition. The enhanced training of the dog has also involved the use of collection of 'cadaver scent' odour from human corpses using remote technical equipment which does not contact the subject. This method is comparable to the simulation of cross contamination. It does however differ in that the remote scent samples recovery does not involve subject matter and therefore is a 'pure' scent sample. The dog has since initial training gained considerable experience in successfully operationally locating human remains and evidential forensic material.
The
E.R.V.D. has successfully in training and in operational casework
located human cadavers, whether in the whole or parts thereof, deposited
surface or sub-surface to a depth of approximately 1 metre shortly
after death (though precise times are not determinable) to the advanced
stages of decomposition and putrefaction through the skeletal. This
includes incinerated remains even if large quantities of accelerant have
been involved. The dog has successfully in training and in operational
casework located a human cadavers in water either from the bank side or
when deployed in a boat where a large area may
be covered using a gridding system.
The dog has also been trained to identify cadaver scent contamination where there is no physically retrievable evidence, due to scent adhering to pervious material such as carpet or the upholstery in motor vehicles.Au cours du dressage et en opération Eddie a réussi à localiser des cadavres humains, ou entiers ou démembrés, sur une surface ou en dessous, à une profondeur d'environ 1 m, entre 'peu de temps après la mort' (sans temps précis déterminable) jusqu'à l'état de squelette en passant par l'état avancé de décomposition. Les restes calcinés sont inclus, même si de grandes quantités d'accélérant ont été employées.
Le chien a aussi été entraîné à détecter la contamination d'odeur de cadavre là où il n'y a plus de substance récupérable, parce que l'odeur s'accroche aux matériaux poreux comme les tapis ou les revêtements des véhicules à moteur.Le "contaminant" est l'objet plus ou moins poreux auquel les COV (composés odorants volatiles) venant du cadavre ont adhéré.
Whereas there may be no retrievable evidence for court purposes this may well assist intelligence gathering in Major Crime investigations. This may be achieved by the dog being deployed directly to the subject area or by scent samples being taken by remote means on sterile gauze pads. The gauze pads are then 'screened' in a line - up formation with the inclusion of a number of control samples and blank sterile pads.
The dog will alert to the presence of cadaver scent whether it is at source or some distance away from a deposition site.
Le chien alerte en
présence d'une odeur de cadavre, que ce soit à la source ou à une
certaine distance du cadavre.
This
enables the use of the dog to identify the venting or exhaust channels
of the scent through fissures in bedrock or watercourses. A geophysical
survey of the area will then reduce the size of the search area. The dog may be used to screen clothing, vehicles or property in a suitable environment. This is completed in a scent discrimination exercise where controls may be included to increase assurity.
The dog has considerable experience in operational recovery of human remains and
evidential forensic material and has trained exclusively using human
remains in the U.S.A. in association with the F.B.I.
It
is possible however that the EVRD will locate the scent source as it
would for 'dead body' scent.
Forensic
testing may not produce evidence but any alert may provide
intelligence to support other factors in the investigation of a
crime.
False Alerts
'False' positives are always a possibility; to date Eddie has not so indicated operationally or in training. In six years of operational deployment in over 200 criminal case searches the dog has never alerted to meat based and specifically pork foodstuffs designed for human consumption. Similarly the dog has never alerted to 'road kill', that is any other dead animal.
My experience as a trainer is that false alerts are normally caused by handler cueing. All indications by the dog are preceded by a change in behaviour.Les fausses alertes positives sont toujours une possibilité. Jusqu'à l'été 2007 où il est allé à PDL, Eddie a eu l'occasion d'alerter en contexte opérationnel et en contexte de dressage. EN 6 ans de déploiement opérationnel recouvrant plus de 200 recherches dans des affaires criminelles, Eddie n'a jamais alerté à la viande animale et spécialement au porc destiné à la consommation humaine (il a été dressé avec de la viande de porc). Il n'a pas non plus alerté face aux cadavres d'animaux accidentés.
This increased handler confidence in the response. This procedure also stops handlers 'cueing' and indication. The dogs are allowed to 'free search' and investigate areas of interest. The handler does not influence their behaviour other than to direct the search.
Eddie et Keela travaillent en tandem de manière à éliminer tout risque de faux positif. Eddie a d'abord été dressé à reconnaître le sang humain et ensuite à reconnaître l'odeur de décomposition du corps humain, tandis que Keela ne détecte que le sang humain. Eddie est donc envoyé en premier sur l'endroit à inspecter. S'il alerte, en l'absence de restes humains visibles, alors on envoie Keela. Si celle-ci alerte aussi, alors on se trouve en présence de sang, au minimum, mais peut-être aussi en présence de cadavre + sang. Si Keela n'alerte pas, alors on sait qu'Eddie a alerté à l'odeur de résidus humains en décomposition.
ST-100 Unit
I have developed the training of the E.V.R.D. to include the screening of scent pads taken from motor vehicles, property or scenes by a Scent Transference Unit. Operational use of the ST-100 is in a developmental and evaluative stage used in conjunction with selective FBI casework. The unit is in a two-part design. The main body is a battery operated electrical device that draws air in at to the front and exhausts through the rear. There is no 're-circulation' of air within the unit. The second part is a 'grilled' hood that fits to the main body. A sterile gauze pad is fitted into the hood. When operated, the unit draws air through the hood and the sterile gauze pad and exhausts through ports to the rear. 'Scent' is trapped in the gauze, which may then be forensically stored for use within scent discrimination exercises.
The ST-100 is cleaned following use in such a manner that no residual scent is apparent. This is checked by control measures where the dog is allowed to search a given area where the ST-100 is secreted. Any response by the dog would suggest contamination. Tests have shown that the decontamination procedures are effective in this case with the dog NOT alerting to the device when completed. Use of the ST-100 is recommended when subject vehicles, property, clothing, premises are to be forensically protected from contamination by the dog, and for covert deployment. At all other times best practice would be for the dog to be given direct access.
MG cite plusieurs affaires que Eddie a contribué à résoudre.
CSI Human Blood Detecting Dog
'Keela' The Crime Scene Investigation (C.S.I.) dog will search for and locate exclusively human blood. She will locate contaminated weapons, screen motor vehicles and items of clothing and examine crime scenes for human blood deposits. She will accurately locate human blood on items that have been subjected to 'clean up operations' or having been subjected to several washing machine cycles. In training she has accurately located samples of blood on property up to thirty-six years old.
In order for the dog to locate the source the blood must have 'dried' in situ. Any 'wetting' once dried will not affect the dog's abilities. Blood that is subjected to dilution by precipitation or other substantial water source prior to drying will soak into the ground or other absorbent material. This may dilute the scent to an unacceptable level for accurate location.
Keela is trained specifically using human blood obtained through the haematology department at Sheffield Northern General Hospital. The blood undergoes strict screening for disease and contamination prior to use. The samples are from a wide range of ethnic backgrounds and are from both male and female sources.
Keela's training and licensing is based around the level of 1 positive screening sample introduced into 200 control articles or 1 positive sample introduced during 6 hours searching in relation to crime scenes or vehicles.
????
The assets may be
deployed upon request of an Senior Investigating Officer (S.I.O.)
following consultation with the appropriate S.M.E.'s and advisors.
The project team makes
decisions on suitability for case deployment. Due to the very nature
of the dog's presence, cross contamination and preservation of vital
evidence at crime scenes must be considered prior to any deployment
in consultation with the senior crime scene coordinator.
Quand MG dit qu'Eddie, l'EVRD, recherche et localise des restes humains et les fluides corporels incluant le sang, il parle de fluides produits par le corps en décomposition et non d'urine, de salive et de sperme. Eddie et Keela n'alerteraient à l'urine, au sperme, aux excréments, etc. que s'ils étaient mélangés à du sang.
Entre 1'15 et 7'25
Whilst it is stated that
the E.V.R D. is originally trained using pig the following notes of
guidance should be considered when assessing indications:
In six years
operational deployment in over 200 cases the dog has never alerted to
meat based foodstuffs.
> The dog has never
alerted to 'road kill'
Alerts given by the dog
where no obvious human remains are found are supported by forensic
evidence I anecdotal witness accounts.
> The dog, a
scavenger, uses its olfactory system to locate food sources, identify
its young and other pack members, enemies and predators over large
distances. It can track its prey identifying a direction of travel.
This entails the dog being able to discriminate the time difference
between footsteps using the sense of smell !> The dog is an animal that's basic function in the wild is to scavenge food and procreate.
> In a domestic environment it responds to humans as a food source and bonds in the manner it would with other pack members.
> The reward of food
and protection / close comfort provides the basis for a system to be
adopted where the dog shows a willingness to respond in response to
the reward. We are thereby able to 'train' the dog using conditioned
responses to stimuli. Repetition and reward then ensure efficiency.
Positive and negative reinforcement then shape the required behaviour
in their role.
Pavlov's theory is used in the case of the E.V.RD. system of alert. He has been 'conditioned' to give a verbal alert when coming into contact with 'dead body scent'. The presence of tangible material is not required to produce the response.
> Although the dog is
'trained' using reward based methods the behaviour shaping and
enforcement regime produces an asset that does not false alert unlike
electronic devices.
> Pseudo scent is a
chemically produced product that its manufacturers claim to resemble
'dead body scent'. Although some trainers have had limited success
when tested on my dogs they showed no interest.
> Operational finds
backed by forensic corroboration have shown that the system adopted
by me in the training of the dogs is both effective and efficient.
Acting in my role of advisor to the U.S. Justice Department I have
facilitated assessment of numerous cadaver search dog teams in the
United States. These dogs are exclusively trained using human cadaver
sources. When I introduced
pig based products into
training assessments 100%! of the animals alerted to the medium.
> The result from
scientific experiment and research to date would tend to support the
theory that the scent of human and pig decomposing material is so
similar that we are unable to 'train' the dog to distinguish between
the two. That is not to say that this may not be possible in the
future.
> The odour target of
cadaver is scientifically explained through 'volatile compounds"
that in a certain configuration are received by the dog as a
receptor. Recognition then gives a conditioned response 'ALERT'.
Despite considerable research and analytical investigation the
compounds cannot be replicated in laboratory processes. Therefore the
'alert' by dogs without a tangible source cannot be forensically
proven at this time.
> 'Dead body scent'
cannot be removed by cleaning. The compounds adhere to surfaces. The
scent can be 'masked' by bleach and other strong smelling odours but
the dog's olfactory system is able to separate odour and identify
specific compounds' and mixes to cellular level. A similar system
would be a device similar to an electron microscope.
> In training the dog
has accurately alerted to a 1 cm cube of pork soaked in petrol for 1
week and then burnt until only a residue remains.
>The dog's olfactory
system is so highly developed that it continues to be efficient at
cellular level:
. Distinguish the time
difference between footprints to give a direction of travel.
. Distinguish live from
dead within minutes.
. Distinguish human blood
from other species where the chemical constituent parts are
identical.
. Identify the EXACT
location of blood so small in size that when forensically recovered
will NOT provide a full DNA strand despite low copy DNA analysis.
> Scientists accept
that there is no forensic testing equipment as discriminatory as the
dogs olfactory system at this present moment in time.
>All research and
training of the dogs within this program is completed in conjunction
with a team of scientists for differing fields of expertise. They
have in the past and will continue to endorse the dogs uses within
the field of homicide investigations.
2
Martin Grime - Audition de mission rogatoire
14.05.2008
Il s'agit ici d'une traduction d'une traduction en portugais de l'original en anglais
I am a retired police offer, previously at the service of the South Yorkshire police. Between August 1-8, 2007, and while working for the South Yorkshire police, I collaborated with the Judicial Police, Portugal, as regards their Operations Task Force.
On the 17th of August 2007, I completed a report for the Head of Investigations of the Judicial Police, which was submitted by the Leicestershire Police. This report is exhibited as MG/1 and identified by the label bearing my signature. The Judicial Police is in possession of the originals of the search reports and the videos showing all searches performed and the reaction of the dogs. In addition to the report, Sam Harkeness of the Progresso National Police Agency sent me by email several written questions sent by the Judicial Police together with a request for a written deposition. This deposition was submitted without me having seen or having knowledge of the final report from the forensic agency responsible for analyzing the evidence submitted in this case.
Questions (de la PJ) et réponses :
* Could you explain the methodology regarding the performance of the dogs in the scope of the undertaken searches ?
* In
order to establish the accuracy of the dogs' performance with respect
to the alerts given when recognizing blood and a body, to what extent
are these indications viable in this particular case ?Martin Grime - Audition de mission rogatoire
14.05.2008
Il s'agit ici d'une traduction d'une traduction en portugais de l'original en anglais
I am a retired police offer, previously at the service of the South Yorkshire police. Between August 1-8, 2007, and while working for the South Yorkshire police, I collaborated with the Judicial Police, Portugal, as regards their Operations Task Force.
On the 17th of August 2007, I completed a report for the Head of Investigations of the Judicial Police, which was submitted by the Leicestershire Police. This report is exhibited as MG/1 and identified by the label bearing my signature. The Judicial Police is in possession of the originals of the search reports and the videos showing all searches performed and the reaction of the dogs. In addition to the report, Sam Harkeness of the Progresso National Police Agency sent me by email several written questions sent by the Judicial Police together with a request for a written deposition. This deposition was submitted without me having seen or having knowledge of the final report from the forensic agency responsible for analyzing the evidence submitted in this case.
Questions (de la PJ) et réponses :
* Could you explain the methodology regarding the performance of the dogs in the scope of the undertaken searches ?
Please refer to my original report included in the summary (MG/1).* Could you provide a thorough description of the dogs' skill and orientation, as well as an interpretation of the dogs' indications in the specific cases ?
Please refer to my original report included in the summary (MG/1).
The interpretation of any alert is given when the dogs recognize a specific odour as a result of a response to the behaviour for which they were trained. This response must then be submitted to a forensic examination in order to draw conclusions. Cette phrase probablement traduite en portugais par le LC, est incompréhensible dans cette langue et a fortiori retraduite en anglais. Cette remarque vaut mutatis mutandis pour toutes les réponses suivantes. L'alerte est un certain comportement mis au point au cours du dressage, que le maître-chien interprète comme la détection, par le chien, de l'odeur qu'il a été entraîné à reconnaître. Cette alerte doit être corroborée par un examen forensique afin d'en tirer des conclusions.
The dogs' alerts are to be considered as an area of interest or possible testing. When specific and reliable this can only be measured for confirmation. In this case in particular, where the dogs alerted there was confirmation by positive results from the forensic examinations. MG ne peut parler ici que de Keela. It is the investigators' responsibility to apply the results of the forensic analysis to the suspects, witnesses and crime scenes.
The dogs' passive CSI alert (la chienne reste figée) provides an indication as per their training and does not vary. The CSI only gives an alert when she is 'positive' that the target of the odour is present and immediately accessible. If she has any doubt she would not give an alert. The EVRD gives an alert by means of a vocal bark. The variations in the vocal alert can be explained by many reasons such as 'thirst' or 'lack of air due to effort'. Every alert can be subject to interpretation, it has to be confirmed. The signals of an alert are only just that. Once the alert has been given by the dog, it is up to the investigator/forensic scientist to locate, identify and scientifically provide the evidence of DNA, etc.
The dogs were not taught any 'tricks'. The EVRD 'signalled' the toy, which at my request was retained by the Judicial Police for future forensic analysis. I have no knowledge of the results of any forensic analysis on the toy.
* With
respect to the cadaver odour on Kate's clothes, could it be undoubtedly
affirmed that those clothes had been in contact with a cadaver ?
OR
Could
the alert have been given because the clothes had been in contact with
other items of clothing, surfaces or objects that could previously have
touched a cadaver, thereby allowing the odour to be transferred ?
There is always a possibility of contamination of odours by transferral. The EVRD does not make a distinction; he responds with a certain behaviour for which he was trained when he recognizes an odour. He does not identify the reasons for the presence of the odour nor does he identify suspects. Forensic confirmation and specialized investigation methods will determine the reasons and the suspicions. In order to undoubtedly affirm there must be a confirmation of the alert signals made by the dog.On ne peut pas dire que MG n'est pas très prudent ! Malheureusement il ne dit rien sur la contamination par transfert.
* The dog EVRD also alerts to blood from a live human being or only from a cadaver ?
The EVRD is trained using whole and disintegrated material, blood, bone tissue, teeth, etc. and decomposed cross-contaminants. Quoi exactement ? 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'. He finds, however, and gives the alert for dried blood from a live human being. Évidemment, puisque le sang séché est du sang en voie de décomposition.
* Taking into account the signals of CSI, could the dog alert to other biological fluids?
The dog that alerts to human blood is trained exclusively for this purpose, and includes its components, plasma, red cells, white cells and platelets. Given the nature of the training, the dog will not alert to urine, saliva, semen, sweat, nasal secretion, vaginal secretion or human skin unless these are mixed with blood. The components of blood are approximately:
Red cells 40-50%
Plasma 55% (of which 95% is water)
White cells
Platelets
DNA can only be removed from white cells.
This would suggest that, of the samples signalled by the dog looking for human blood, approximately 5% are available for DNA tests.
The dogs do not get confused. They transmit a behavioural response inspired by the recognition of the odour for which they were trained.
Cross-contamination is immediate.Quelle différence entre cross-contamination, contamination et transferral ?
cross-contamination : inadvertent transfer of bacteria or other contaminants from one surface, substance, etc., to another especially because of unsanitary handling procedures.
contamination : développement dans une substance de bactéries ou d'autres contaminants en raison du contact de la substance avec le contaminant ou de la présence d'un ingrédient contaminé.
transferral : the act of moving something from one location to another
* How long can a trace of blood remain at a scene and be detected by the CSI dog ?
During both training and operations, the CSI dog correctly located and signalled the presence of blood from 1960. This is not at all surprising. If enough blood is present so that the dog can recognize its odour, he will locate it and alert to its presence. There is no time restriction as regards the recognition of the odour by the dog. Mais il faut de la substance. Blood, however, is subject to deterioration such as time and other natural processes such as dilution due to rain and other reactive chemical agents.
I cannot comment on what the dogs think. However, from a forensic point of view and from confirmations of scientific testimonies, the dogs appear to be extremely exact. But, forensic confirmation is required in all cases so as to be included as proof. MG dit clairement ici que la confirmation forensique est exigée par les tribunaux, pas par l'enquête criminelle. The CSI dog is trained using only human blood. And using a wide spectrum of donors to ensure that the dog does not individualize them.La technique pour obtenir ce résultat est intéressante. Elle consiste fondamentalement, au cours du dressage, à ne pas récompenser le chien s'il réagit à des restes non humains.
The EVRD used to be trained using swine as their odour is the closest to that of humans. But most of the time, however, the dog was trained using the odour of a human cadaver. Operationally, the dog has ignored large amounts of animal remains/bones when locating human decomposition.
I cannot. Très prudent. In this case, for example, not all the alert signals have been investigated by the appropriate agencies in order to provide forensic comparations, in spite of indications to the contrary. It also should be taken into account that the procedures for forensic testing are still less discriminating than the system of dogs' smell.Où MG semble dire fermement que l'odorat du chien est un plus puissant discriminateur d'odeurs que tous les tests forensiques existant actuellement.
During training, the dogs are barely rewarded for positive alert signals regarding targets of known substances.
* At any time, did Gerald McCann address, either in Portugal or the United Kingdom, the performance of the dogs in this case ?
I never met nor spoke to Gerald McCann. However I do know that he addressed my head supervisor at the time, the South Yorkshire Head of Police, Mr. Meredydd Hughes.
