The Double Clue — Agatha Christie

Poirot is called in by Marcus Hardman, a collector of various antique precious objects, to investigate a jewel robbery. The theft occurred from his safe when he was holding a small tea party at his house. He showed his guests his collection of medieval jewels and later discovered that the safe had been rifled and the objects taken. Four of his guests had the opportunity to take the items - Mr Johnston, a South African millionaire only just arrived in London; Countess Vera Rossakoff, a refugee from the Russian revolution; Bernard Parker, a young and effeminate agent for Mr Hardman, and Lady Runcorn, a middle-aged society lady whose aunt is a kleptomaniac.