"In your own office?"

"No," replied the other readily, "I did most of my work in Mr. Lyne's office-at his request," he added. A bold statement to make to a man who knew that Lyne suspected him of robbing the firm. But Milburgh was nothing if not bold.

"Did he also give you the key of his desk?" asked the detective dryly.

"Yes, sir," beamed Mr. Milburgh, "of course he did! You see, Mr. Lyne trusted me absolutely."

He said this so naturally and with such assurance that Tarling was staggered. Before he had time to speak the other went on:

"Yes, I can truthfully say that I was in Mr. Lyne's confidence. He told me a great deal more about himself than he has told anybody and--"

"One moment," said Tarling, and he spoke slowly. "Will you please tell me what you did with the revolver which you found on Mr. Lyne's desk? It was a Colt automatic, and it was loaded."

Blank astonishment showed in Mr. Milburgh's eyes.

"A loaded pistol?" he asked, raising his eyebrows, "but, my dear good Mr. Tarling, whatever are you talking about? I never found a loaded pistol on Mr. Lyne's desk-poor fellow! Mr. Lyne objected as much to these deadly weapons as myself."

Here was a facer for Tarling, but he betrayed no sign either of disappointment or surprise. Milburgh was frowning as though he were attempting to piece together some half-forgotten recollection.

"Is it possible," he said in a shocked voice, "that when you examined my house the other day it was with the object of discovering such a weapon as this!"

"It's quite possible," said Tarling coolly, "and even probable. Now, I'm going to be very straightforward with you, Mr. Milburgh. I suspect you know a great deal more about this murder than you have told us, and that you had ever so much more reason for wishing Mr. Lyne was dead than you are prepared to admit at this moment. Wait," he said, as the other opened his mouth to speak. "I am telling you candidly that the object of my first visit to these Stores was to investigate happenings which looked very black against you. It was hardly so much the work of a detective as an accountant," he said, "but Mr. Lyne thought that I should be able to discover who was robbing the firm."

"And did you?" asked Milburgh coolly. There was the ghost of a smile still upon his face, but defiance shone in his pale eyes.

"I did not, because I went no further in the matter after you had expressed your agreement with Mr. Lyne that the firm had been robbed by Odette Rider."

He saw the man change colour, and pushed home his advantage.

"I am not going to inquire too closely into your reasons for attempting to ruin an innocent girl," he said sternly. "That is a matter for your own conscience. But I tell you, Mr. Milburgh, that if you are innocent-both of the robbery and of the murder-then I've never met a guilty person in my life."

"What do you mean?" asked the man loudly. "Do you dare to accuse me--?"

"I accuse you of nothing more than this," said Tarling, "that I am perfectly satisfied that you have been robbing the firm for years. I am equally satisfied that, even if you did not kill Mr. Lyne, you at least know who did."

"You're mad," sneered Milburgh, but his face was white. "Supposing it were true that I had robbed the firm, why should I want to kill Mr. Thornton Lyne? The mere fact of his death would have brought an examination into the accounts."

This was a convincing argument-the more so as it was an argument which Tarling himself had employed.

"As to your absurd and melodramatic charges of robbing the firm," Milburgh went on, "the books are now in the hands of an eminent firm of chartered accountants, who can give the lie to any such statement as you have made."

He had recovered something of his old urbanity, and now stood, or rather straddled, with his legs apart, his thumbs in the armholes of his waistcoat, beaming benignly upon the detective.

"I await the investigation of that eminent firm, Messrs. Dashwood and Solomon, with every confidence and without the least perturbation," he said. "Their findings will vindicate my honour beyond any question. I shall see this matter through!"

Tarling looked at him.

"I admire your nerve," he said, and left the office without another word.

CHAPTER XXI

COVERING THE TRAIL

Tarling had a brief interview with his assistant Whiteside, and the Inspector, to his surprise, accepted his view of Ling Chu's confession.

"I always thought Milburgh was a pretty cool customer," Whiteside said thoughtfully. "But he has more gall than I gave him credit for. I would certainly prefer to believe your Chink than I would believe Milburgh. And, by the way, your young lady has slipped the shadow."

"What are you talking about?" asked Tarling in surprise.

"I am referring to your Miss Odette Rider-and why on earth a grown-up police officer with your experience should blush, I can't imagine."

"I'm not blushing," said Tarling. "What about her?"

"I've had two men watching her," explained Whiteside, "and whenever she has taken her walks abroad she has been followed, as you know. In accordance with your instructions I was taking off those shadows to-morrow, but to-day she went to Bond Street, and either Jackson was careless-it was Jackson who was on the job-or else the young lady was very sharp; at any rate, he waited for half an hour for her to come out of the shop, and when she didn't appear he walked in and found there was another entrance through which she had gone. Since then she has not been back to the hotel."

"I don't like that," said Tarling, a little troubled. "I wished her to be under observation as much for her own protection as anything else. I wish you would keep a man at the hotel and telephone me just as soon as she returns."

Whiteside nodded.

"I've anticipated your wishes in that respect," he said. "Well, what is the next move?"

"I'm going to Hertford to see Miss Rider's mother; and incidentally, I may pick up Miss Rider, who is very likely to have gone home."

Whiteside nodded.

"What do you expect to find out from the mother?" he asked.

"I expect to learn a great deal," said Tarling. "There is still a minor mystery to be discovered. For example, who is the mysterious man who comes and goes to Hertford, and just why is Mrs. Rider living in luxury whilst her daughter is working for her living at Lyne's Store?"

"There's something in that," agreed Whiteside. "Would you like me to come along with you?"

"Thanks," smiled Tarling, "I can do that little job by myself."

"Reverting to Milburgh," began Whiteside.

"As we always revert to Milburgh," groaned Tarling. "Yes?"

"Well, I don't like his assurance," said Whiteside. "It looks as if all our hopes of getting a clue from the examination of Lyne's accounts are fated to be dashed."

"There's something in that," said Tarling. "I don't like it myself. The books are in the hands of one of the best chartered accountants in the country, and if there has been any monkey business, he is the fellow who is certain to find it; and not only that, but to trace whatever defalcations there are to the man responsible. Milburgh is not fool enough to imagine that he won't be found out once the accountants get busy, and his cheeriness in face of exposure is to say the least disconcerting."

Their little conference was being held in a prosaic public tea-room opposite the House of Commons-a tea-room the walls of which, had they ears, could have told not a few of Scotland Yard's most precious secrets.

Tarling was on the point of changing the subject when he remembered the parcel of books which had arrived at the accountant's office that morning.

"Rather late," said Whiteside thoughtfully. "By Jove! I wonder!"

"You wonder what?"