Island of Bones (Louis Kincaid Mysteries) by P. J. Parrish.

Set in the late 1980s, the newest addition to Parrish's Louis Kincaid mystery series (Thicker Than Water) lures readers in from the outset when a young woman's bullet-ridden corpse is found tangled in mangrove roots on Florida's beautiful, tropical seacoast. Kincaid, a former cop turned private investigator, is hired by a woman who fears that her father, Frank Woods, a middle-aged, nondescript librarian with murky connections to several missing women dating back as far as 35 years, may be the killer. Although all signs point to Woods's guilt, his confession and apparent suicide never sit well with Kincaid. He reluctantly teams up with Mel Landeta, a gruff but ultimately likable local police officer who's losing his eyesight, and they return to the last place Woods visited-the Island of Bones. The tension builds to a near palpable level as the pair uncover secrets that are as dark and warped as the primal landscape Parrish vividly describes. World-weary, contemplative Landeta is the perfect foil for Kincaid, a true man of action. Their camaraderie and unspoken understanding, combined with Parrish's crisp dialogue and skill at stringing out the suspense, are what make this carefully constructed mystery so absorbing.