Which jogged my memory. Here is guy-who-knows-everything Ken Jennings, writing almost six years ago:
Structurally, these aren’t fantasy novels at all. They’re fair-play mysteries in wizard’s clothing–novels with not just plots and characters and setpieces, but “solutions” as well. J. K. Rowling is justly praised for her elaborate and meticulous world-building, but I’m convinced that a lot of that endless detail is just there for standard detective-novel purposes: to distract, to confound, to envelop the real “clues” in a Cloak of Invisibility.
I bet Rowling’s first post-Harry Potter book–talk about a hard act to follow–will be a classic mystery of some kind. I don’t know if it’ll be a hard-boiled gumshoe case, a true-crime police procedural, a classic manor-house throwback, or what, but it’ll be a mystery novel. She’s been writing them all along, after all. It’s just that no one’s noticed.
Casual Vacancy excepted, Mr. Jennings certainly had Rowling pegged. Go read his post, by the way -- it's not long, but the stuff I snipped out is a cool examination of mystery story tropes as deployed in the Harry Potter books. (Which I plan to re-read this winter.)