The Albert Gate Mystery : Being Further Adventures of Reginald Brett, Barrister Detective

In an Albert Gate mansion a number of Turkish gentlemen had taken up their residence for the purpose of having some fifty-odd wonderful diamonds belonging to the sultan cut and polished. They had enlisted the protection of the English Government, and the police equipment and caution exercised in regard to the safety of the Turks and the jewels were such that the country was electrified when one morning four Turks were found dead in their rooms, the diamonds were missing, and the particular Assistant Secretary in the Foreign Office [...] is found to have mysteriously disappeared. --New York Times