Unreliable dogs don't work. You don't need to look at them but rather the people who are unreliable in this case. Zapata was unreliable not the dogs that alerted to cadaver residual scent! You know the ones that like to open their mouths and you don't believe a word they say!
What is Residual Scent?
Residual is defined by Webster's dictionary as - leaving a residue remaining effective for some time.
Within this paper we are using the term in conjunction with decomposing human scent. Residual scent searches are those conducted when no physical form is present. Residual scent is what is left when the decomposing item has been removed. It is something we cannot see and humans cannot necessarily smell.
One of the questions we are commonly asked as forensic canine handlers is "How long will scent last in any given situation?" This is a very complicated question, but we want to begin to unravel the secrets. We know some of the elements that will affect residual scent are heat/sun, wind, humidity and rain.
Our first project was conducted in a closed, unused building. Items were placed in different rooms for 5 hours and then removed.
Results
Each dog participating in this project was able to find most or all of the locations where the decomposing scent articles had been. We saw dogs, which varied, from full alert and pinpointing to general interest in the room or area.
What we have found so far is; residual scent will last 1 year in a building with minimum environmental influence, or human disturbance. Even after the objects where the scent source had been were removed, the dogs were able to locate the rooms, general area, or pinpoint where it had been.
Each time we have worked the problem we have included teams that had not worked the area before. We now have had 16 teams work the residual scent problem. The dogs have ranged from veteran cadaver trained certified teams to 1 year old puppies (who have been training from 8 weeks of age on cadaver and residual scent).
http://www.csst.org/residual_scent.html
