Caselli and Torre novels

"When a woman is beheaded in a park outside Rome and her six-year-old son goes missing, Deputy Captain Colomba Caselli and Dante Torre, both still recovering from personal catastrophes, team up to solve the series of killings and abductions that ensues. As they follow the ever-more-bizarre trail of clues, one thing becomes clear: what's really going on is much darker than anyone imagined"-- Provided by publisher.