The Black Diamonds certainly are very handsome. May I now request you to tell me,’ she repeated, with a certain assumption of hauteur, ‘the reason of all these enquiries?’

“‘The reason is simple enough, madam,’ replied the detective abruptly. ‘Those diamonds were the property of Her Majesty the Queen of “Bohemia”, and were stolen from Their Majesties’ residence, Eton Chase, Chislehurst, on the 5th of July last year.’

“‘Stolen!’ she repeated, aghast and obviously incredulous.

“‘Yes, stolen,’ said old Marsh. ‘I don’t wish to distress you unnecessarily, madam, but you will see how imperative it is that you should place me in immediate communication with Mr Vanderdellen, as an explanation from him has become necessary.’

“‘Unfortunately, that is impossible,’ said Mrs Vanderdellen, who seemed under the spell of a strong emotion.

“‘Impossible?’

“‘Mr Vanderdellen has been dead just over a year. He died three days after his return to New York, and the Black Diamonds were the last present he ever made me.’

“There was a pause after that. Marsh – experienced detective though he was – was literally at his wits’ ends what to do. He said afterwards that Mrs Vanderdellen, though very young and frivolous outwardly, seemed at the same time an exceedingly shrewd, far-seeing businesswoman. To begin with, she absolutely refused to have the matter hushed up, and to return the jewels until their rightful ownership had been properly proved.

“‘It would be tantamount,’ she said, ‘to admitting that my husband had come by them unlawfully.’

“At the same time she offered the princely reward of £10,000 to anyone who found the true solution of the mystery: for, mind you, the late Mr Vanderdellen sailed from Havre for New York on July the 8th, 1902, that is to say, three clear days after the theft of the diamonds from Eton Chase, and he presented his wife with the loose gems immediately on his arrival in New York. Three days after that he died.

“It was difficult to suppose that Mr Vanderdellen purchased those diamonds not knowing that they must have been stolen, since directly after the burglary the English police telegraphed to all their Continental colleagues, and within four-and-twenty hours a description of the stolen jewels was circulated throughout Europe.

“It was, to say the least of it, very strange that an experienced businessman and shrewd collector like Mr Vanderdellen should have purchased such priceless gems without making some enquiries as to their history, more especially as they must have been offered to him in a more or less ‘hole-in-the-corner’ way.

“Still, Mrs Vanderdellen stuck to her guns, and refused to give up the jewels pending certain enquiries she wished to make. She declared that she wished to be sued for the diamonds in open court, charged with wilfully detaining stolen goods if necessary, for the more publicity was given to the whole affair the better she would like it, so firmly did she believe in her husband’s innocence.

“The matter was indeed brought to the High Courts, and the sensational action brought against Mrs Vanderdellen by the representative of His Majesty the King of ‘Bohemia’ for the recovery of the Black Diamonds is, no doubt, still fresh in your memory.

“No one was allowed to know what witnesses Mrs Vanderdellen would bring forward in her defence. She had engaged the services of Sir Arthur Inglewood, and of some of the most eminent counsel at the Bar. The court was packed with the most fashionable crowd ever seen inside the Law Courts; and both days that the action lasted Mrs Vanderdellen appeared in exquisite gowns and ideal hats.

“The evidence for the Royal plaintiff was simple enough. It all went to prove that the very day after the burglary not a jeweller, pawnbroker, or diamond merchant throughout the whole of Europe could have failed to know that a unique parure of black diamonds had been stolen, and would probably be offered for sale. The Black Diamonds in themselves, and out of their setting, were absolutely unique, and if the late Mr Vanderdellen purchased them in Paris from some private individual, he must at least have very strongly suspected that they were stolen.

“Throughout the whole of that first day Mrs Vanderdellen sat in court, absolutely calm and placid. She listened to the evidence, made little notes, and chatted with two or three American friends – elderly men – who were with her.

“Then came the turn of the defence.

“Everybody had expected something sensational, and listened more eagerly than ever as the name of Mr Albert V. B. Sedley was called. He was a tall, elderly man, the regular angular type of the American, with his nasal twang and reposeful manner.

“His story was brief and simple. He was a great friend of the late Mr Vanderdellen, and had gone on a European tour with him in the early spring of 1902. They were together in Vienna in the month of March, staying at the Hotel Imperial, when one day Vanderdellen came to his room with a remarkable story.

“‘He told me,’ continued Mr Albert V. B. Sedley, ‘that he had just purchased some very beautiful diamonds, which he meant to present to his wife on his return to New York. He would not tell me where he bought them, nor would he show them to me, but he spoke about the beauty and rarity of the stones, which were that rarest of all things, beautiful black diamonds.

“‘As the whole story sounded to me a little bit queer and mysterious, I gave him a word of caution, but he was quite confident as to the integrity of the vendor of the jewels, since the latter had made a somewhat curious bargain. Vanderdellen was to have the diamonds in his keeping for three months without paying any money, merely giving a formal receipt for them; then, if after three months he was quite satisfied with his bargain, and there had been no suspicion or rumour of any kind that the diamonds were stolen, then only was the money, £500,000, to be paid.

“‘Vanderdellen thought this very fair and above-board, and so it sounded to me. The only thing I didn’t like about it all was that the vendor had given what I thought was a false name and no address; the money was to be paid over to him in French notes when the three months had expired, at an hotel in Paris where Vanderdellen would be staying at the time, and where he would call for it.

“‘I heard nothing more about the mysterious diamonds and their still more mysterious vendor,’ continued Mr Sedley, amidst intense excitement, ‘for Vanderdellen and I soon parted company after that, he going one way and I another. But at the beginning of July I met him in Paris, and on the 4th I dined with him at the Élysée Palace Hotel, where he was staying.

“‘Mr Cornelius R. Shee was there too, and Vanderdellen related to him during dinner the history of his mysterious purchase of the Black Diamonds, adding that the vendor had called upon him that very day as arranged, and that he (Vanderdellen) had had no hesitation in handing him over the agreed price of £500,000, which he thought a very low one. Both Mr Shee and I agreed that the whole thing must have been clear and above-board, for jewels of such fabulous value could not have been stolen since last spring without the hue and cry being in every paper in Europe.

“‘It is my opinion, therefore,’ said Mr Albert V.