With Private Eyes by Eileen Wilks

Claudia Barone was the perfect choice to shadow Ethan Mallory and discover what he knew about the sabotage of her family’s business. She could steamroll anyone. Anyone but Ethan. The cagey P.I. would never tell her his prime suspect was her brother. Nor could he hide his attraction — red-hot, out of control and licking at her heels...

To a society deb like Claudia, Ethan was rough around the edges, and used caveman tactics to get his way. Yet that earthy animal attraction threatened to eat her alive. Claudia had never been bested by a man, but working closely with Ethan, desperately trying to keep her hands off him, she wondered if she’d met her match....