yeah …nah, this was a book. I don’t think I’ve ever seen a ‘police procedural’ book. And if that’s what this was trying to be, it really didn’t work.
About The Alienist, it didn’t seem to me like they really got the motive wrong. The motive was always “whoever the guy is, this killings make him feel better because of twisted stuff in his childhood” - that was pretty much set all the way through. It was just a matter of getting the right twisted stuff. That book gets a bit closer to “thriller” than “murder mystery” anyway, which has its own rules
McBain turned the procedural into a genre that everyone jumped onto, but there were earlier examples that go as far back as you want to stretch the definition.
I agree with the page that Lawrence Treat definitely wrote procedurals in the 1940s. And I’m surprised that it mentions John Creasy’s iffy Inspector West series but not the Gideon series (as by J. J. Marric) that started in 1955 and really were proper proceurals.
Has the following been done? Someone was not murdered, their death was accidental. But suspicion falls on someone who is acting very shifty about the death for some reason, and the mystery isn’t about the non-existent motive for murder but why the suspect isn’t being forthcoming about it.