Blood upon the Snow — Hilda Lawrence

"Miss Lawrence creates horror atmosphere with good skill, the hard way, with a light touch that leaves no brush marks. A few snowflakes, the mere suggestion of sinister sound, the barest hint of screaming silence, and the reader's hackles come away from his collar." -- The New York Times Book Review
"Smooth handling by East -- and the author." -- Kirkus.
Private detective Mark East arrives at Crestwood, an elegant estate, to serve as a private secretary to archaeologist Joseph Stoneman. At least, East is supposed to be a secretary. Mr. Stoneman's nervous manner suggests that he's actually in need of a bodyguard. The estate's other residents -- including a troubled hostess who confines herself to her room and a strangely solemn child -- contribute to the fearful atmosphere. After a snowstorm completely isolates the estate from outside contact and the occupants start dying under mysterious circumstances, East must identify the murderer before it's too late for the entire household.
A selection of the Haycraft-Queen Definitive Library of Crime