Chase James Hadley. Figure it out for Yourself

When Perelli saved Vic Malloy's life, the private eye promised to return the favour - on the house, whenever required. Three weeks later, Perelli is framed on a kidnap charge. The victim, Dedrick, was married to Serena, one of the richest women in the world, who paid half a million dollars to get him back and apparently wasted her money. When Malloy starts investigating, all his leads end up dead. Dedrick was a man nobody loved, with a past nobody wanted to talk about - suddenly, even Serena was willing to buy Malloy off, with the biggest fee he'd ever seen. However, that left Perelli set for the gas chamber and Malloy liked to pay his commitments. But even Malloy had not reckoned on being imprisoned in an old dank mine, by Dedrick himself, with man-eating rats for company.