The Five-Grand Cross, by Alan Ritner Anderson (epub/Kindle)
For ten nerve-racking days, Mae Cole hadn’t stepped outside the hotel. If the pasty-faced man with the yellow teeth wasn’t watching her, it was someone else, because she was always conscious of eyes following her in the public rooms. She could not trust the staff either—the bellhops, the waiters, the busboys, chambermaids, switchboard operators, or the manager himself. The enemy had connections in high places and money to burn.