All the Days Were Summer — Robert Funderburk

Their idyllic way of life in the shady bayous is shattered when the mayor of Evangeline is assassinated.
Dylan St. John and his wife have left behind the mean streets of Louisiana's capital city for a cypress cabin on the edge of the trackless Atchafalaya Basin. As the chief deputy of the sleepy bayou town of Evangeline, he and Susan are growing to love the serenity and solitude of the swamps as well as the Cajun food and celebrations.
But this tranquil life is shattered when the mayor of Evangeline is assassinated, beginning a puzzling pattern of murders that claim the lives of mayors throughout South Louisiana. Law enforcement authorities are baffled, especially by the bizarre methods the assassin employs. And Dylan, driven by his own suspicions, finds he must battle the very forces that are meant to uphold justice.
A Headlong Rush to Stop the Assassin Leads Through the Depths of the Swamps to the Heart of New Orleans.