The Mangrove Coast by Randy Wayne White

Florida marine biologist Doc Ford lands hip-deep in hot water when the daughter of a dead war buddy calls asking for help. Her mother has vanished without a trace in South America--while with an unsavory companion--and all of her money has disappeared with her. Doc's efforts to find her take him from the steamy jungles of Colombia to the violent streets of Panama and onto the trail of the vilest man he has ever met. More sinister, though, is the person following him--a shadowy figure who, seems to appear out of nowhere, leaving only death in his wake...

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