Buried Prey by John Sandford

Nothing special but consistently enjoyable like the rest of the (21 book) series. Gives a peek into the beginning of Lucas Davenport's career.  In 1985, Davenport was a young cop with a reputation for recklessness, and the girls' disappearance was a big deal. His bosses ultimately declared the case closed, but he never agreed with that. Now that he has a chance to investigate it all over again, one thing is becoming increasingly clear: It wasn't just the bodies that were buried. It was the truth.