I tried asking some cops, but they are now allowed to divulge those kind of details on how their K-9s work. Basically when you read stories about how a bank was robbed for example, and the dog was able to pick out the robbers smell compared to everyone elses' smell. I was just wondering how to explain in my story how a dog is able to isolate a smell, when it's in a building full of several different people. Also if the villain has to worry about getting away with the crime, he would have to figure out how to throw the dog off his own sent. Does anyone know how these things work? I tried looking it up but could not find many details on it. Thanks for the input. I really appreciate it.