S03E06 - The Double Clue

Poirot is called in to investigate a jewel robbery by Marcus Hardman, a collector of various antique precious objects. 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 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.
Poirot examines the scene of the crime and finds a man's glove and a cigarette case with the initials "BP". He visits Bernard Parker who appears suspicious when he states that the glove isn't his but vehemently denies owning the cigarette case, nevertheless Poirot finds the twin of the glove in the hallway of Parker's house.