Five

Five is definitely not a book for the faint-hearted, but Ursula Archer delivers great suspense, unexpected plot twists, and multi-dimensional characters in this international bestseller.
A woman's corpse is discovered in a meadow. A strange combination of letters and numbers has been tattooed on the soles of her feet.
Detective inspector Beatrice Kaspary from the local murder squad quickly identifies the digits as map coordinates. These lead to a series of gruesome discoveries as she and her colleague Florin Wenninger embark on a bloody trail – a modern-day scavenger hunt using GPS navigation devices to locate hidden caches.
The "owner" of these unofficial, unpublished geocaches is a highly calculating and elusive fiend who leaves his victims' body-parts sealed in plastic bags, complete with riddles that culminate in a five-stage plot. Kaspary herself becomes an unwilling pawn in the perpetrator's game of cat and mouse as she risks all to uncover the motives behind the murderer's actions.