You know what you really need is an English countryside murder mystery mashup with a splatterpunk supernatural horror movie. Think of it as the Re-Animator of Algernon Blackwood.
You got your level proper countryside Midsommer Murders group of coppers, only now they're not dealing with vengeful old aunties but the rage of nature itself, the raw an unchecked anger of the land given life, the darkness of the woods, the deep sunk pain of rocks and roots. The metaphysical embodiment of natural spirits takes the form of trees, growing form nowhere inside quiet drawing room, through the aging and satisfied ladies at gossip, ripping their bodies into bloody chunks of gore and offal.
But the steadfast inspectors stay at the same level despite investigating crime scenes like the aftermath of an Evil Dead movie, unflappably seeking out the mundane clues leading nowhere and puttering about at home with loving wife and doting daughter. For each tangle of thorns stretched over with gruesome skin and impaled bodies, for each body consumed alive by locusts, for the houses swallowed by earth leaving nothing but a blood soaked skeleton behind, life trundle onward undisturbed.
Which is not to say the protagonist is undisturbed. A historian and preservationist, they're seeking to maintain and increase the records for right if way paths throughout England, much to the annoyance of various gentleman about this quiet country town beside by horror and death. And it falls to them to make the discovery that the right of way paths are not as they're meant to be, no, it seems there's been some moving of landmarks and stone boundaries, an offsetting of the path letting lands fall increasingly into private hands.
Yet those paths and stones and markers were not merely guides. They were lines, sigils, locks and gates to hold back the will of the woods from the lands of men. For a time. For just a small but fair space. A trade of stewardship and watchful wards, but men long forgot the promise of caretaking or what the wards kept at bay.
And now they are paying, as the historian struggles to find the means to close the way. And the steadfast inspector begins to uncover a land grabbing plot. And as time counts down the fae and green and deep eldritch magic of old reaches shadows further into the tidy little village. It may have survived countryside murders for decades, but it will be lucky to last a week under these conditions.