Death by Revelation — Jack J. Lee

This is book two of the Sustainable Earth series. The survivors in Salt Lake City have finally gotten the zombie and vampire infestation under control. Unfortunately, the greatest monsters have always been human. There are times when it's an advantage to be insane; an apocalypse is one of them. The US Mountain States have always been home to religious cults. The Fundamentalist Latter Day Saints have been waiting for the End of Days. They were prepared. A new prophet has risen and a Holy War has begun.