Sky Like Bone — V.J. Chambers

It's sticky and hot outside, and Wren Delacroix and Caius Reilly are bored. Ever since Hawk Marner's appeal cast doubt on their ethics, it's been crickets from police departments who want their help. With nothing to do but wait for the appeal, the two decide they could use a distraction. An FBI agent staying the facility that houses their new offices is trying to crack something in Northern California that could be a set of cult killings. They don't really investigate cult killings. But it could be a serial killer. Or, it could be nothing at all. There are no bodies. There are just six couples who have all disappeared after frequenting an outreach program called Love Over Want. It's not really their kind of thing, but... well, they are bored.