t　from　a　master　of　the　game　such　as　the　Marquis。〃

〃And　you　honestly　mean　that　Richard　Knighton　is　a　well…known　criminal；　who　has　been　at　this　business　for　years？〃

Poirot　nodded。

〃One　of　the　chief　assets　of　the　gentleman　called　the　Marquis　was　his　plausible；　ingratiating　manner。　You　fell　a　victim　to　his　charm；　Monsieur　Van　Aldin；　when　you　engaged　him　as　a　secretary　on　such　a　slight　acquaintanceship？〃

〃I　could　have　sworn　that　he　never　angled　for　the　post；〃　cried　the　millionaire。

〃It　was　very　astutely　done　…　so　astutely　done　that　it　deceived　a　man　whose　knowledge　of　other　men　is　as　great　as　yours　is。〃

〃I　looked　up　his　antecedents　too。　The　fellow's　record　was　excellent。〃

〃Yes；　yes；　that　was　part　of　the　game。　As　Richard　Knighton　his　life reproach。　He　was　well…born；　well…connected；　did　honourable　service　in　the　war；　and　seemed　altogether　above　suspicion；　but　when　I　came　to　glean　information　about　the　mysterious　Marquis；　I　found　many　points　of　similarity。　Knighton　spoke　French　like　a　Frenchman；　he　had　been　in　America；　France；　and　England　at　much　the　same　time　as　the　Marquis　was　operating。　The　Marquis　was　last　heard　of　as　engineering　various　jewel　robberies　in　Switzerland；　and　it　was　in　Switzerland　that　you　had　e　across　Major　Knighton；　and　it　was　at　precisely　that　time　that　the　first　rumours　were　going　round　of　your　being　in　treaty　for　the　famous　rubies。〃

〃But　why　murder？〃　murmured　Van　Aldin　brokenly。　〃Surely　a　clever　thief　could　have　stolen　the　jewels　without　running　his　head　into　a　noose。〃

Poirot　shook　his　head。　〃This　is　not　the　first　murder　that　lies　to　the　Marquis's　charge。　He　is　a　killer　by　instinct；　he　believes；　too；　in　leaving　no　evidence　behind　him。　Dead　men　and　women　tell　no　tales。

〃The　Marquis　had