MOO, If LE is using SAR canine(s) in the home, I don't think it would be related to Gannon's scent. Rather, I would postulate that LE found something that they wish to either rule in, or rule out, as to whether or not that something, or the owner of it, or someone who had been in possession of it, was in that home. Possibly something related to a third party yet to be named.
There would be no reason to take a dog in to that home to gain Gannon's scent, or TS's for that matter, as any item that either one of them used regularly could be used to give the dog that scent. MOO