The Riley Thomas series sits somewhere between a cozy (she's an amateur sleuth) and a police procedural (darker tone than a cozy with more detail given to some of the crimes). Riley is a reluctant medium who can communicate with ghosts, and she uses that ability to help her solve cold cases. This series is much darker than my cozies and I'd classify it as “horror lite.” There is sexual content (though not much) and adult language, so I recommend this series to readers 18+.
Reading order:
Coming next: A Grave Disturbance