Cabaret Montmartre

A little after 1am, The Duchess, star of Cabaret Montmartre was murdered. It soon emerged that her extremely expensive pearl necklace had disappeared. The director had gotten the necklace from the Ostend mafia on the condition that they would then be welcome in the Cabaret.
Now the director has hired you to find the necklace as soon as possible!
Was it that pianist full of revenge? The director who was secretly in love with The Duchess? The barman who had just lost all his money or maybe her husband who did not accept her working in the Cabaret?
Find the culprit and the necklace quickly, because the Ostend mafia is already on your heels!