The real problem, Dabrose reflected, as his horse tore through the forest pursued by, well, nothing he could see at the moment, but surely something, was one of scale.
In the grand scheme of things, the theft of the key was a massive problem for the country. It was a black eye on a monarchy already suffering a lack of popularity and stirs of discontent. After a ruinous war, the loss of a sacred artifact of (supposed) arcane power wasn’t going to win you any popularity contests. Find a thief—a minor functionary, but major enough to look like he might actually have pulled it off—and publicly, messily execute him, however, and you both show the populace your ability to get things done and send some fear toward the people sowing discontent. You don’t even really need to get the key back.
Dabrose was, he knew, a minor functionary. A minor functionary who was maybe fucking the Princess, which the Queen suspected to be the case. The right levels of access, and a slightly checkered past. A perfect fit.