What follows in this article teaches us what causes odor and scent to remain after the source has left or has been removed. It is chemical in nature, and therefore just knowing what happens is likely all you need. I included the whole article as there some other interesting facts. The reason for this article was a recent court case where the judge wanted to know how a narcotic odor could remain after the product was removed. 

Advances in the use of odor as forensic evidence through optimizing and standardizing instruments and canines

Have you checked the Canine Resource Quick Link on the right side of this page? There you will see a snapshot of the articles we have available to a member of the USPCA. Check back, as we change the information regularly.

Interprets

The word or variation of the word interprets is most often used by canine handlers in reports, training records, and testimony. They describe how they interpreted behavior changes or a final response given by the dog upon sniffing a trained odor.