"The Reindeer Clue" by Edward D. Hoch

The Misadventures of Ellery Queen ed. Josh Pachter and Dale C. Andrews, p. 73–77

Two days before Christmas, Ellery Queen and his father, Inspector Richard Queen, are visiting the Children's Zoo when they are asked to help find out who murdered gossip columnist-turned-blackmailer Casey Sturgess, whose body is found in the reindeer pen.

With one woman and two men present as suspects, Ellery identifies the killer from dabs of Sturgess's blood left on a placard containing lines from Clement Clarke Moore's poem "A Visit from St. Nicholas".

Carla Coupe of publisher Wildside Press sent me a review copy of this March 2018 anthology of Queen pastiches and parodies. First published in The National Inquirer in 1975 with Ellery Queen's byline, "The Reindeer Clue" was for years thought to be the last story written by the original authors, a feat I'm not surprised master Ed Hoch pulled off.