Phoebe Atwood Taylor writing as Alice Tilton: Cold Steal (1980)

From the Publisher:
WELCOME HOME TO MURDER!
Writing as Alice Tilton, Phoebe Atwood Taylor once again embroils her scholarly sleuth Leonidas Witherall in enough foul play to challenge his wits to their limit. Returning to the Cape after a trip around the world, Witherall investigates some odd doings on the train: he is knocked unconscious and kidnapped. When he finally manages to get home, he discovers the body of Miss Medora Winthrop in his garage. Even the amazing Witherall is hard put to solve this one.

ANOTHER MYSTERY CLASSIC
from
Foul Play Press

Phoebe Atwood Taylor writing as Alice Tilton: Cold Steal. Mayhem on a train and murder at home welcome Leonidas Witherall to Cape Cod. Woodstock, VT.: Countryman Press / Foul Play Press, 1980, ISBN: 0914378546, 287 p., $4.95.