Dance with Darkness by Sheri-Lynn Marean

Twenty-eight year old cat shifter Enyowas has spent the last sixteen years taking care of his family. As the Tom of the Spokane Spite cat clan, he also runs Spokane’s Enforcement for preternatural protection—a secret organization that protects supes and humans from the predators that would hunt them.
But when a series of strange events leads to his sister’s death, Enyowas realizes they have a serial killer.
Filled with guilt over the past he’s never been able to get out of his head, and now for his sister, Enyowas only wants to be alone to grieve. But duties don’t wait for anyone. So when he’s asked to help a rare female leopard shifter, he goes. Only, he isn’t prepared for how she makes him feel. How she makes him want something he never thought to have.
Betrayal has left Enyowas guarded and unavailable. But as he learns the truth about what’s really going on, Enyowas has a choice to make. Will he accept what is right in front of him, or continue to protect his heart from more hurt?