Found Money by James Grippando

Single mother Amy Parkens feels trapped by a boring job, low pay, and no time for her young daughter. But that's before $200,000 in cold, hard cash arrives in an unmarked box. Desperately needing the money, Amy fears a setup or a connection to her mother's suicide 20 years earlier. So she sets out to find the source.
A decent, responsible small-town doctor, Ryan Duffy didn't expect to inherit a fortune from his electrician father, who had millions stashed away in the attic. Did it come from extortion, robbery, or some other terrible crime? Painful as it is, Ryan is drawn to his father's dark past, determined to find the truth.
Desperate for answers, Amy and Ryan soon cross paths on a dangerous quest that takes them through a labyrinth of deception and blackmail - leading them to a man of unfathomable power who holds the key to their fortunes...and their lives.