le suspicion could attach to Richard Knighton。 But like all great men … and the Marquis was a great man … he had his weaknesses。 He fell genuinely in love with Miss Grey； and suspecting her liking for Derek Kettering； he could not resist the temptation to saddle him with the crime when the opportunity presented itself。 And now； Monsieur Van Aldin； I am going to tell you something very curious。 Miss Grey is not a fanciful woman by any means； yet she firmly believes that she felt your daughter's presence beside her one day in the Casino Gardens at Monte Carlo； just after she had been having a long talk with Knighton。 She was convinced； she says； that the dead woman was urgently trying to tell her something； and it suddenly came to her that what the dead woman was trying to say was that Knighton was her murderer！ The idea seemed so fantastic at the time that Miss Grey spoke of it to no one。 But she was so convinced of its truth that she acted on it … wild as it seemed。 She did not discourage Knighton's advances； and she pretended to him that she was convinced of Derek Kettering's guilt。〃
〃Extraordinary；〃 said Van Aldin。
〃Yes； it is very strange。 One cannot explain these things。 Oh； by the way； there is one little point that baffled me considerably。 Your secretary has a decided limp … the result of a wound that he received in the ost decidedly did not limp。 That was a stumbling…block。 But Miss Lenox Tamplin happened to mention one day that Knighton's limp had been a surprise to the surgeons who had been in charge of the case in her mother's hospital。 That suggested camouflage。 When I was in London I went to the surgeon in question； and I got several technical details from him which confirmed me in that belief。 I mentioned the name of that surgeon in Knighton's hearing the day before yesterday。 The natural thing would have been for Knighton to mention that he had been attended by him during the war； but he said nothing … and that little point； if nothing else； gave me the last final assurance that my theory of the crime was correct。 Miss Grey； too； provided me with a cutting； showing that there had been a robbery at Lady Tamplin's hospital during the time that Knighton had been there。 She realized that I was on the same track as herself when I wrote to her from the Ritz in Paris。
〃I had some trouble in my inquiries there； but I got what I wanted … evidence that Ada Mason arrived on the morning after the crime and not on the evening of the day before。〃
There was a long silence； then the millionaire stretched out a hand to Poirot across the table。
〃I guess you know what this means to me； Monsieur Poirot；〃 he said huskily。 〃I am sending you round a cheque in the morning； but no cheque in the world will express what I feel about what you have done for me。 You are the goods； Monsieur Poirot。 Every time； you are the goods。〃
Poirot rose to his feet； his chest swelled。
〃I am only Hercule Poirot；〃 he said modestly； 〃yet； as you say； in my own way I am a big man； even as you also are a big man。 I am glad and happy to have been of service to you。 Now I go to repair the damages caused by travel。 Alas！ my excellent Georges is not with me。〃
In the lounge of the hotel he encountered a friend … the venerable Monsieur Papopolous； his daughter Zia beside him。
〃I thought you had left Nice； Monsieur Poirot；〃 murmured the Greek as he took the detective's affectionately proffered hand。
〃Business pelled me to return； my dear Monsieur Papopolous。〃
〃Business？〃
〃Yes； business。 And talking of business； I hope your health is better； my dear friend？〃
〃Much better。 In fact； we are returning to Paris tomorrow。〃
〃I am enchanted to hear such good news。 You have not pletely ruined the Greek ex…Minister； I hope。〃
〃I？〃
〃I understand you sold him a very wonderful ruby which … strictly entre nous … is being worn by Mademoiselle Mirelle； the dancer？〃
〃Yes；〃 murmured Monsieur Papopolous； 〃yes； that is so。〃
〃A ruby not unlike the famous 'Heart of Fire'？〃
〃It has points of resemblance； certainly；〃 said the Greek casually。
〃You have a wonderful hand with jewels； Monsieur Papopolous。 I congratulate you。 Mademoiselle Zia； I am desolate that you are returning to Paris so speedily。 I had hoped to see some more of you now that my business is acplished。〃
〃Would one be indiscreet if one asked what that business was？〃 asked Monsieur Papopolous。
〃Not at all； not at all。 I have just succeeded in laying the Marquis by the heels。〃
A far…away look came over Monsieur Papopolous' noble countenance。
〃The Marquis？〃 he murmured； 〃now why does that seem familiar to me？ No … I cannot recall it。〃
〃You would not； I am sure；〃 said Poirot。 〃I refer to a very notable criminal and jewel robber。 He has just been arrested for the murder of the English lady； Madame Kettering。〃
〃Indeed？ How interesting these things are！〃
A polite exchange of farewells followed； and when Poirot was out of earshot。 Monsieur Papopolous turned to his daughter。
〃Zia；〃 he said； with feeling； 〃that man is the devil！〃
〃I like him。〃
〃I like him myself；〃 admitted Monsieur Papopolous。 〃But he is the devil； all the same。〃
Chapter 36
BY THE SEA
The mimosa was nearly over。 The scent of it in the air was faintly unpleasant。 There were pink geraniums twining along the balustrade of Lady Tamplin's villa； and masses of carnations below sent up a sweet； heavy perfume。 The Mediterranean was at its bluest。 Poirot sat on the terrace with Lenox Tamplin。 He had just finished telling her the same story he had told to Van Aldin two days before。 Lenox had listened to him with absorbed attention； her brows knitted and her eyes sombre。
When he had finished she said simply： 〃And Derek？〃
〃He was released yesterday。〃
〃And he has gone … where？〃
〃He left Nice last night。〃
〃For St Mary Mead？〃
〃Yes； for St Mary Mead。〃
There was a pause。
〃I was wrong about Katherine；〃 said Lenox。 〃I thought she did not care。〃
〃She is very reserved。 She trusts no one。〃
〃She might have trusted me；〃 said Lenox； with a shade of bitterness。
〃Yes；〃 said Poirot gravely； 〃she might have trusted you。 But Mademoiselle Katherine has spent a great deal of her life listening； and those who have listened do not find it easy to talk； they keep their sorrows and joys to themselves and tell no one。〃
〃I was a fool；〃 said Lenox； 〃I thought she really cared for Knighton。 I ought to have known better。 I suppose I thought so because … well； I hoped so。〃
Poirot took her hand and gave it a little friendly squeeze。 〃Courage； Mademoiselle；〃 he said gently。
Lenox looked very straight out across the sea； and her face； in its ugly rigidity； had for the moment a tragic beauty。
〃Oh； well；〃 she said at last； 〃it would not have done。 I am too young for Derek； he is like a kid that has never grown up。 He wants the Madonna touch。〃
There was a long silence； then Lenox turned to him quickly and impulsively。 〃But I did help； Monsieur Poirot … at any rate I did help。〃
〃Yes； Mademoiselle。 It was you who gave me the first inkling of the truth when you said that the person who mitted the crime need not have been on the tra