A Necessary Evil by Christina Kaye

In 1977, blood-brothers Frankie Cartwright and Kurt Jamison were inseparable. But when a shocking event touched someone they both loved, the boys handled the trauma differently…
Kurt became a cop. Frankie grew up to be a notorious crime lord.

Forty years later, when Frankie’s teenage granddaughter Mollie is kidnapped and Kurt is assigned to her case, the former best friends are forced to work together. However, Kurt wants to conduct the investigation within the confines of the legal system, while Frankie would rather use his less-than-legal resources to find her—and punish her abductor.

With the cloud of a dark secret casting a shadow over each man’s endeavor to find Mollie, Kurt and Frankie exhaust every resource at their disposal in an effort to save her and serve up their own individual brand of justice.