SCENT COLLECTION
In order to use the scent from a crime scene with any dog, the scent must first be collected in some manner so that it can be presented to the dog to smell. There are a number of ways scent can be collected.
First, the dog can be "direct scented", that is, the dog is allowed to smell the actual object the suspect touched, wore, or handled. Most Search & Rescue dogs are scented in this manner. The problem with this manner is the dog can ruin other evidence on that object, such as fingerprints, DNA, etc.
Second, the scent can be obtained by "swabbing" the surface the criminal had contact with...for example the steering wheel of a get-away car. Again, there goes your other evidence that might be on the object.
Third, the scent can be obtained by "passive transfer" where a gauze pad is laid on the surface the suspect had contact with, and the pad is left there for some time...usually between 15 minutes to an hour. This manner of collection is very time consuming, and the transfer of the scent is unreliable.
Fourth, and in my opinion by far the best method of scent collection, is the use of a vacuum device such as the "Scent Transfer Unit", or "S.T.U. 100", or just plain "STU". This device utilizes a low-draft vacuum to draw the scent onto a sterile gauze pad, and leaves the other evidence intact and undisturbed. These gauze pads, or "scent pads", are then stored in double plastic bags, and labeled as evidence. These scent pads are what is presented to the dog to smell. The use of the STU makes it possible to obtain scent from virtually any object. Most sophisticated law enforcement agencies, along with their local prosecuting attorneys will find the use of the STU, or some similar device, to be the preferred method of scent collection.
Just for the record, I do not receive anything in return for this, or any, referral I give the STU. I just firmly believe it is the best tool out there for the collection and preservation of crime scene scent. Show me something better, I'll jump on its band-wagon. In a non-criminal scenario there is nothing wrong with using a missing person's pillow case as your scent item. On the other hand, I use the STU for ALL scent collections I do so I am always consistent. When testifying, I never have to stop and think, "Now how did I collect scent this time?". I know. I always do it the same way.
The S.T.U. 100. was originally developed by Bill Tolhurst, and further refined and marketed by Larry Harris. See links for more info.
or "click" here.
The S.T.U. 100 is available to law enforcement.
