The Riddle Key — Jane Drager

Antiques expert Marina Cavanaugh is offered an exorbitant salary to appraise a dead man's estate. For a chance at easy money, she accepts the job but soon discovers hidden cameras in the darkest, gloomiest house she's ever seen. Jonathan Blandish, who hired her, wants to know why his murdered brother left a series of cryptic messages implicating Marina. Even a layman can see the house contains only rummage-sale junk. But his brother's forty-million-dollar fortune is missing, and Marina is the key. From the second they meet, Marina and Jonathan are at odds. He's too bossy and reminds her of her abusive father. She's too independent ... and too beautiful for him to ignore. A second murder and Marina's disappearance raises the danger level. Convinced she was captured for the clues in the riddles, Jonathan races against time to find her before the killer realizes she knows nothing at all.