In article <4a7bf677$0$2528$da0feed9@news.zen.co.uk> "Mark Lewis"  writes:
>"JohnR"  wrote:

>>>> to search for probable cause using dogs when dogs are wrong four times
>>>> out of five is, I believe,not right.

>> saying dogs can't smell is a bit silly.

>What part of the 20% success rate do you attribute to the dog smelling the
>drug and what to the officer observing if the person being sniffed looks
>worried they might be detected?
>
>I propose a simple experiment: compare the success rate of the officer with
>that of an illusionist using a magic box that people are told can detect
>drugs.  I would expect the illusionist to do far better than the officer.

There's a difference between saying dogs can detect traces of drugs and
whether or not drugs are actually found.

There are several reasons for not finding drugs when an officer claims the
dog alerted:

1) The dog did not really alert (which is what you are claiming, and something
   I know does happen).

2) The dog did alert, but did so because the dog knew the officer wanted
   him/her to alert (when using dogs for finding things, the handler has to
   be very careful not to give cues to the dog -- I'm certain some police
   officers will give cues to the dog since they aren't impartial observers,
   and if the dogs aren't particularly trained to ignore such cues...).

3) The dog did alert, but alerted due to traces of drugs that are no longer
   in evidence (in other words, there were drugs in contact with something
   the suspect is wearing or has in his/her possession, but those drugs have
   already been used or discarded or whatver).  [Note that at one time -- and
   it may still be true -- equipment to detect cocaine on paper money was
   rendered useless by the fact that almost all money is tainted with cocaine
   due to residue being transfered from one bill to another.]

4) The dog did alert, but because the dog smelled something other than drugs
   (which does happen when dogs aren't properly trained, or the training isn't
   properly reinforced on a regular basis).

But that doesn't alter the fact that a properly-handled, well-trained dog will
be able to locate things through scent that no human or machine can currently
detect.  Dogs have been known to alert diabetic owners to dangerously low
blood sugars, they have located cancer when none could be detected with
standard tests, etc.

Dogs have also been used for centuries to track felons and missing persons,
and are used nowadays to locate bodies (both dead and alive) in collapsed
buildings and under avalanches.

You shouldn't denigrate the ability of dogs to detect things nasally just
because that ability is misused by overzealous police officers.

-Pete Zakel
 (phz@seeheader.nospam)

"You do not examine legislation in the light of the benefits it will convey
 if properly administered, but in the light of the wrongs it would do and the
 harms it would cause if improperly administered."
							-Lyndon Johnson