Humans have motive for lying; highly trained dogs do not.
"The evidence from two highly trained cadaver dogs who found the ‘smell of death’ in several places in the holiday apartment where the McCanns were staying - and in a car they hired three weeks later
As suspicions grew in the minds of the Portuguese police that Doctors Kate and Gerry McCann might know what had happened to their daughter, and might even have been involved in some way in her disappearance, the police turned to the British police to help them determine whether Madeleine might have died in Apartment 5A in Praia da Luz, where her parents had been staying from 28th April to 3rd May, the day she was reported missing.
They turned for advice to experienced Leicestershire detective Mark Harrison, who, after a week’s visit to Praia da Luz in July 2007 - in which he analysed all the evidence - advised that the Portuguese police should proceed on the working assumption that Madeleine had died in the McCanns’ apartment, and her body hidden or otherwise disposed of. He then brought in a top police dog handler, Mr Martin Grime, who had two highly-trained springer spaniels under his command: ‘Eddie’, who could detect human cadaverine, the so-called smell of death, and ‘Keela’, in effect a ‘blood-hound’, who could detect the presence of blood.
Dogs, it should be noted, are known to have a sense of smell 10,000 times as strong as that of humans, which is almost beyond comprehension given that we ourselves have such a highly developed sense of smell. The two dogs, trained and used successfully by top police dog-handler Martin Grime over many years, had the ability to use their faculties in two highly specific areas.
Eddie, who has been called ‘the cadaver dog’, can detect the presence of human ‘cadaverine’, a special chemical released from a dead body, usually after the body has been dead for at least two hours (sometimes as short as an hour-and-a-half). It’s important to understand that Eddie is trained
only to scent the presence of the special type of cadaverine released by a
human corpse. The scent of death from animals is a
different form of cadaverine. Keela is a dog trained specifically to detect the presence of blood. She is therefore what is popularly known as a ‘blood-hound’. She has been trained to ignore decomposing body materials other than human blood, freezing with her nose as near to the blood as possible without touching the item, to enable scientists to recover the sample quickly and efficiently. She can even pick out traces of blood after clothing or weapons have been washed many times; when Keela was working on the Abigail Witchalls case, she found eight pieces of blood-stained clothing in just one day.
Claims have been made by the McCanns and their team of legal and PR advisers about the alleged unreliability of cadaver dogs, including suggestions that they have on occasions mistaken pork for cadaver scent. But cadaver dogs have an excellent track record and have been used successfully in several murder trials. They are able to detect the smell of death up to dozens of feet below the surface and even after a body has lain there for years. Spectacular examples of their work can be viewed on many websites on the Internet. In addition, Mr Harrison and Mr Grime, who trained Eddie and Keela, patiently explained that the dogs had traced the ‘smell of death’ - human cadaverine - on around 200 previous occasions.
They had never once been wrong."
Source :
http://www.cwporter.com/mccann.htm
