Has it been published what breed the "hunting" dogs are? Since he wears a tracker when he is off their property, we can assume they were not typically confined when he was gone, I'd guess. Could they have been for the purpose of serving as guard dogs and as early heads up if someone entered the property? With grounds, lots of green space, and a nearby river with lots of tributaries possibly providing access undetected by road and neighbors, guard dogs might have been comforting in hus circumstances. Does anyone know how long they've had these dogs? Just since his financial troubles or since he abruptly left his job? Given his age, his professional work tht involved "knowing things" and "how things work", access to both sensitive information and to high stakes money, I'm leaning toward this not being a simple "he got mad and offed his wife then himself in a mad rage", although it could easily be written off as such. That's the way they do it, you know. So many people flying out of windows and hanging themselves unexpectedly and with zero clue or forewarning even minutes beforehand.
But the dogs... I'm very curious about the dogs, and about his level of interest in actually hunting. Did he? Or did he just target practice?
If he was "enticed" to leave his job suddenly against all logic, similar enticements (or deterrents) can be made all the way up and down the chain. When one isn't enough, the other will be & escalating increments will be applied to the screws on each end until success is reached. I hope the investigation has multiple tiers on enough multiple fronts to successfully guard against this in the investigation hierarchy.