Over at The Curmudgeonly Clerk there has been some discussion of this post.
Actually, at first I took "unable to verify" as an admission that the dog had previously alerted when there were no drugs found. The officer understood the question, she just wasn't going to admit straight up that her dog makes errors. However, to state what I believe the officer's final position was (after 2-3 pages of transcript which I was too lazy to type in completely): when her dog alerted there might not be drugs present at that time but there was residue from prior presence which precluded the confirmation of drugs. Thus the dog does not fail; humans fail in not being able to confirm the presence currently or in the past. Police learn to make statements like this because they are too often rewarded for them by the courts who are looking for any reason not to suppress evidence. So the Clerk is dead on in his analysis.
Dedman suggests that perhaps people should be more careful of how their statements might be read once they are transcribed. That's a mighty high standard during the give and take of a trial. People just aren't thinking about the transcript during a trial. Here, the officer was trying her best to spin things her way to win with the trial judge and I was doing my best to make it obvious that she and her partner had violated the Fourth Amendment by searching my client's truck after the client had been judged not to have drugs, the dog had not alerted on the truck, and the dog had alerted on the passenger but upon a search of his person no drugs were found. The judge stopped us during argument, ordered a transcript and required us to brief the matter.1
1 In Va. State trial courts my suppression motion usually doesn't say much more than "They violated Client's 4th Amendment rights." This is because no more is required and the prosecutor is not required to answer my motion. I have offered more than once to pre-brief my motions if the Assistant Commonwealth Attorney on the other side will file a reply brief and not use any paralegals or interns to write the brief or research the matter (in at least one jurisdiction where I practice briefs seem to be written by the law student interns and the prosecutor, like as not, may come in arguing something entirely different than what is in the brief). No prosecutor has accepted this when I offered it.