Hunterland by Dana Claire
Liam Hunter has warded off hungry vampires, slayed monstrous beasts, and put agonized spirits to rest since he could hold a stake. When trouble comes through the Hunterland message board, alerting them that nurses are dying at high schools across Wisconsin in a string of fishy "suicides", the Hunter family hits the road to save the day.
The trail leads to Falkville Falls, where Liam clashes with Olivia Davis, whose maddening family seems inexplicably embroiled in this haunting mess. Olivia has always mothered her little sister, Pepper. But when the Hunter family opens her eyes to the hidden underworld of real monsters prowling the dark, she realizes she can't protect Pepper from this newest threat by herself. Can the two families work together to uncover who or what is responsible before the next murder, or will this vicious death cycle have no end?