I am a little loathed to comment on the tragic death of this dog as from so far away, as I only have the information here, but for what it's worth here is my prospective. Firstly I am a retired UK police officer trained in both operationaland training duties. Since 1992 I have worked in the private sector training LE dogs and personnel in Europe and the US.
From the first day any police officer (or anyone else for that matter) takes charge of his dog to begin his career as a 'dog handler', the total care and welfare of the dog rests with him. As far as administration is concerned he dog is a mere resource among many. The subject of canine welfare both physical and emotional is covered in the handlers initial course (or should be but not always the case in the US), but notwithstanding common sense should prevail.
If this handler did indeed leave his dog for 12 hours in a vehicle I would suggest that it is questionable that he should have a career in law enforcement let alone spe******e in the dog section. For the department the loss of the dog is going to be expensive a duel trained Police Patrol/Narcotic Detector Dog runs between $10/15k, but it's not just the cash, this will no doubt impact on the public. I trust the department in question will give consideration when next accepting letters for future handlers, not everyone is suitable for these duties.
We have a saying, 'There are two kinds of police dog handlers, dog handlers and a man with a dog!', unfortunately for the dog in question he was the latter.
Sorry guys didn't mean to preach, I'm sitting in the office in France, it's early in the morning and I haven't had a coffee yet.......................