Something prompted them to bring in the second dog when they got to the b
last night the police in their interview said that its normal procedure to call in dogs from somewhere else to verify a hit by their dogs
did that make sense?
I have no experience in LE search procedures but I do have a lot of experience in scientific procedures. Same rules apply if you want your conclusions to be accepted either by the court (in LE's case) or by the scientific community (in my case).
Doing an experiment at least twice is a MUST - SO they couldn't just use one dog.
Having someone outside your circle of co-workers VALIDATE your results is also a MUST. A second dog from somewhere else to verify a hit by their dogs is done so that they assure that the two dogs have different training!!! different handlers!!! Why? The want to eliminate the possibility of two dogs arriving to the same wrong conclusion (something the defence will try to say in the future). How do you do that? Eliminating any similarities between the dogs. Hence the need to bring a dog that wasn't theirs, didn't have the same conditions like the other dog.
My explanation