Written by William Le Queux
Copyright 1921
8th story in the collection The Luck of the Secret Service. It is to the Soviet city of Kharkov that Claud Heathwaite is dispatched by the Chief, his orders being to ascertain if what was feared was really happening there. After some time in the city, he knew to prove it and stop it would require a certain type of help, like that possessed by his own fiancee, Myrtle.
Here are the pages I have of it.