Long Gone by Denise Grover Swank

Welcome to Lone County, Arkansas, where every corner holds a secret, and the past is never really buried.
Disgraced ex-detective Harper Adams has traded her badge for a desk job at her father's law firm, a move as dull as the small town she's returned to. But things take a turn when a local woman wants to declare her missing husband dead, five years after his mysterious disappearance.
With her father's firm representing the man's missing wife, Harper seizes the opportunity to delve back into her investigative roots. Her search leads her back to James Malcolm, a former crime boss turned tavern owner, who has his finger on the pulse of every shadowed corner. His offer to help with her investigation catches her by surprise.
Why would a former criminal offer his help unless he has something to gain?