I'm researching and plotting out my first historical mystery and I'm wondering if there are other historical mystery writers out there on this forum. While I'm thoroughly enjoying the research process and have found a lot of good material, one aspect of the research seems most challenging: learning how criminal investigation would have been done at the time. I've turned up a couple of treatises on policework and fingerprinting from the period (one of which I've been able to access so far) but I still feel like this type of resource won't really ground me in the experience. I could try finding records from period crimes, but would that be much better? What I think I really want (and am trying furiously to find though I doubt such a thing exists or if it does it's in someone's attic somewhere not in a library where I could see it) is a diary or a memoir of a law enforcement officer working during the period (and if possible in the same state as my novel).
I know recommending resources is difficult when you don't know the period and location well (in my case late 1910's Georgia), but if there are others on this forum who have conducted this type of research, it might be beneficial to hear about the types of sources you consulted, the general research path that you took and what was most helpful.
Of course as the story takes place nearly a hundred years ago (so there's no one with first hand knowledge) and I imagine that criminal investigation methods varied widely from one county to the next, I could probably get away with guessing on some details, but I prefer to be as accurate as possible, something I'm sure folks on this subforum can understand. I'd really appreciate any advice or just stories from the research trenches!