Wildfire at Midnight — Mary Stewart

I FOLLOWED MARCIA TO HER ROOM...
She pushed her door open and groped for the light switch.
When the lights went on I heard her gasp. She was standing as if frozen, her back to me, her hands up to her throat.
Then she screamed, a high, tearing scream.
"The murderer. Oh my God, the murderer. . . ."
She grabbed my arm and pointed to the bed, her lips shaking so much that she couldn't speak coherently.
I stared down at the bed, while the slow goose flesh pricked up my spine.
Lying on the coverlet was a doll, the kind of frivolous doll I had seen dozens of times.
But this one was different.
It was lying flat on its back on the bed, with its legs straight out and its hands crossed on its breast. The contents of an ash tray had been scattered over it, and a great red gash gleamed across its neck, where its throat was cut from ear to ear...

A young crofter's daughter is cruelly and ritually murdered on the bleak Scottish mountainside. In the deceptively idyllic Camasunary Hotel nearby, the beautiful but troubled, Gianetta Brooke cannot seem to escape her pain or her past -- not even in the remote hotel on the Scottish Isle of Skye. When she discovers that her ex-husband has booked into the same hotel, the peaceful holiday for which she had hoped takes on quite another complexion.

Very soon Gianetta finds herself tangled in a web of rising fear and suspicion. One of her fellow guests, however, is also hiding secrets... and a skill and penchant for murder. And now the killer only has eyes for Gianetta....