The Man in the Mist
Written by
Agatha Christie
Copyright 1929
First published in The Sketch (Dec. 3, 1924), then in 2 issues of Ellery Queen's Mystery Magazine (US - Sep. 1961 & Aus - Nov. 1961).
[G.K.Chesterton's Father Brown] "Recovering from the setback of failing to solve their latest case, Tommy and Tuppence are recouping with some cocktails when they stumble upon their next opportunity: a famous actress, who appears to be terrified of a superstition."
9th story in the collection .