Night of the Panther — E.C. Ayres

Sometime private eye Tony Lowell is ready to take his finally refurbished wooden schooner on its maiden voyage. Then his friend Lena Bedrosian calls. Lena's cousin, conservation officer Marge Pappas, has just been found dead, her bullet-riddled body floating in Corkscrew Swamp. Tony agrees to investigate, and soon he's managed to stir up a hornet's nest of poachers, local militia, corrupt sheriff's deputies, powerful businessmen, and even a state senator.