The White Cliffs Mystery

It starts off with a corpse thrown from a train. I assume it was a dummy.

Scotland Yard are brought in to investigate and the dead man was Edward Matrion. A research engineer doing top secret government work involving the latest guided missile technology.

His employer find out that one of the top secret blueprints is missing.

Was Matrion engaged in selling the secret plans to an enemy country?

Superintendent Duggan discover that Matrion's wife is very ill. His bank accounts show a withdrawal of a large amount of cash. Indicating that he might be being blackmailed. Also his secretary is missing, reportedly on holiday.

Edgar Lustgarten regarded the case as sensational. It certainly has urgency with national security at stake. I did wonder why no alarm bells went off when Duggan was first told that secretary was on holiday.