The Chalk Pit : A Mystery (Ruth Galloway Mysteries)

"Far below Norwich is a maze of old mining tunnels. When Ruth Galloway is called to examine a set of human remains in one of them, she notices the bones are almost translucent, a sign they were boiled soon after death...As Ruth and Nelson investigate thetunnels, they hear rumors of secret societies, cannibalism, and ritual killings. And when a dead body is found with a map of what seems to be the full maze, they realize their hunt for the killer has only just begun--and that more bodies may be underfoot"--