Gone But Not Goodbye (Nathan Miccoli #2)
A.R. Kennedy

Lily is haunted by the kidnapping, consumed by thoughts of him. Nathan is burdened with an inept partner, who may ruin his career as an NYPD detective, just as it's beginning.
Will Nathan be able to solve the mystery of why his partner's family is harassing him? And solve the last robbery case he may ever be assigned?
But the biggest mystery in his life is Lily.