A Morning For Flamingos (Dave Robicheaux, Bk. 4)

A routine assignment transporting two death-row prisoners to their executions goes fatally wrong, leaving Dave Robicheaux brutally wounded and his partner dead.
  
Obsessed with revenge, Dave is persuaded by the DEA to go undercover into the torrid sleepy depths of New Orleans, a volatile world of Mafia drug-running and Cajun voodoo magic. He becomes irrevocably snarled in the nightmarish web surrounding Mafia don Tony Cardo and must put himself against his own worst fears in order to survive.