Ten Years Gone by HP Newquist

Every November for nearly a decade, a body has been found hanging and mutilated from a tree in the town of Kerrville. As the tenth anniversary of the slaughter approaches, the killer leaves clues that indicate there will be only one more murder. 

A reality show and its celebrity host decide that this last murder could be the ratings they've always wanted, and they are determined to find the murderer before the police do. 

But the killer thinks that is a very, very bad idea.