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The Radium Thieves is a short story by Agatha Christie which was first published in issue 1617 of The Sketch on 23 January 1924. It was the fourth of a series of connected stories to be published in the magazine under the series title The Man who was Number Four: Further Adventures of M. Poirot".

In January 1927, the stories in the series were woven together with minor changes and some additional connecting paragraphs and then published in novel form as The Big Four. For background as to the circumstances of this, see The Big Four. The short story here formed the basis for chapter 7 of The Big Four (also with the title "The Radium Thieves").

Later the same year, in June 1927, the story was published in The Blue Book Magazine. The text in this latter case was the same (with minor abridgements) as in the novel and so this can be considered a serialization of the novel rather than a republication of the original short story carried in The Sketch.

The original text of the story as found in The Sketch was therefore quite rare until 2016. In that year, HarperCollins published The Big Four (Detective Club Edition), a collection of the "Big Four" short stories as they first appeared in The

In the Sketch series, this story is preceded by The Lady on the Stairs and followed by In the House of the Enemy.


Poirot and Hastings are still in Paris from the last case. Madame Olivier tells Poirot that some thieves had tried to steal radium from her but had failed. Believing they would try again, Poirot tries to set a trap for the radium thieves.

Plot summary[]

(may contain spoilers - click on expand to read)

A man in an overcoat, obviously an operative of The Big Four, comes and tries to warn off and then bribe Poirot to lay off the Big Four. Hastings wants to call the police. The man attacks him. After a scuffle, the man escapes, leaving behind a notebook. There is an entry for a "meeting of the council" at an address at 11 a.m. The note is signed with a large figure 4. But Poirot ignores it. It is too obviously a trap or a ruse to get him out of the way.

At 11.30 Madame Olivier summons Poirot. Two men broke into her laboratory and attempted to steal her supply of radium but failed break open the safe. She would be keeping the radium for only two more days so if they intended to try again it would have to be soon. Poirot plans a trap. He and Hastings board a train for Calais. The train is stopped by a friend of Poirot who pulls the emergency stop handle. In the commotion, Poirot and Hastings step off the train and secretly return to Paris.

They get to Olivier's villa but are ambushed by thugs and brought inside and down into an underground chamber. There Olivier reveals herself to be Number Three. She intends to kill them to put an end to their interference but she offers Poirot a last request. Poirot asks for a cigarette from his case. Olivier leaves Poirot's arms still tied up but inserts a cigarette into his mouth. Poirot now tells her that the cigarette in his mouth is a mini blow pipe which contains a poisonous dart. Olivier is forced to untie Hastings, who then unties Poirot. They bind and gag Olivier and then escape. Poirot reproaches himself bitterly for falling into the trap. At least they now know who Number 3 is but they cannot report this fact to the police. Olivier is probably the greatest scientist in France, an idol and heroine to the French. No one would believe them.


Research notes[]

Comparison between the original story and the version in the novel[]

  • Apart from a few paragraphs at the beginning to link to the Halliday story in the previous chapter, the novel and the short versions are the same.

Film, TV, or theatrical versions[]

Agatha Christie's Poirot[]

Publication history[]

Original short story text[]

Part of Novelisation[]

  • 1927: The Big Four, William Collins and Sons (London), 27 January 1927, Hardcover, 282 pp
  • 1927: The Big Four, Dodd Mead and Company (New York), 1927, Hardcover, 276 pp
  • 1927: The Blue Book Magazine, Vol. 45 No. 2 (Chicago), June 1927.