Wapping and Shadwell. His dark, curly hair clung clammily about the brown forehead; his skin was stained, they told me. He wore a gold ring in one ear, and three fingers of the left hand were missing.

"It was almost the same with Mason." The river police inspector was speaking. "A week ago, on a Wednesday, he went off in his own time on some funny business down St. George's way—and Thursday night the ten-o'clock boat got the grapnel on him off Hanover Hole. His first two fingers on the right hand were clean gone, and his left hand was mutilated frightfully."

He paused and glanced at Smith.

"That lascar, too," he continued, "that you came down to see, sir; you remember his hands?"

Smith nodded.

"He was not a lascar," he said shortly. "He was a dacoit."

Silence fell again.

I turned to the array of objects lying on the table—those which had been found in Cadby's clothing. None of them were noteworthy, except that which had been found thrust into the loose neck of his shirt. This last it was which had led the police to send for Nayland Smith, for it constituted the first clew which had come to light pointing to the authors of these mysterious tragedies.

It was a Chinese pigtail. That alone was sufficiently remarkable; but it was rendered more so by the fact that the plaited queue was a false one being attached to a most ingenious bald wig.

"You're sure it wasn't part of a Chinese make-up?" questioned Weymouth, his eye on the strange relic. "Cadby was clever at disguise."

Smith snatched the wig from my hands with a certain irritation, and tried to fit it on the dead detective.

"Too small by inches!" he jerked. "And look how it's padded in the crown. This thing was made for a most abnormal head."

He threw it down, and fell to pacing the room again.

"Where did you find him—exactly?" he asked.

"Limehouse Reach—under Commercial Dock Pier—exactly an hour ago."

"And you last saw him at eight o'clock last night?"—to Weymouth.

"Eight to a quarter past."

"You think he has been dead nearly twenty-four hours, Petrie?"

"Roughly, twenty-four hours," I replied.

"Then, we know that he was on the track of the Fu-Manchu group, that he followed up some clew which led him to the neighborhood of old Ratcliff Highway, and that he died the same night. You are sure that is where he was going?"

"Yes," said Weymouth; "He was jealous of giving anything away, poor chap; it meant a big lift for him if he pulled the case off. But he gave me to understand that he expected to spend last night in that district. He left the Yard about eight, as I've said, to go to his rooms, and dress for the job."

"Did he keep any record of his cases?"

"Of course! He was most particular. Cadby was a man with ambitions, sir! You'll want to see his book. Wait while I get his address; it's somewhere in Brixton."

He went to the telephone, and Inspector Ryman covered up the dead man's face.

Nayland Smith was palpably excited.

"He almost succeeded where we have failed, Petrie," he said. "There is no doubt in my mind that he was hot on the track of Fu-Manchu! Poor Mason had probably blundered on the scent, too, and he met with a similar fate. Without other evidence, the fact that they both died in the same way as the dacoit would be conclusive, for we know that Fu-Manchu killed the dacoit!"

"What is the meaning of the mutilated hands, Smith?"

"God knows! Cadby's death was from drowning, you say?"

"There are no other marks of violence."

"But he was a very strong swimmer, Doctor," interrupted Inspector Ryman. "Why, he pulled off the quarter-mile championship at the Crystal Palace last year! Cadby wasn't a man easy to drown. And as for Mason, he was an R.N.R., and like a fish in the water!"

Smith shrugged his shoulders helplessly.

"Let us hope that one day we shall know how they died," he said simply.

Weymouth returned from the telephone.

"The address is No.—Cold Harbor Lane," he reported. "I shall not be able to come along, but you can't miss it; it's close by the Brixton Police Station. There's no family, fortunately; he was quite alone in the world. His case-book isn't in the American desk, which you'll find in his sitting-room; it's in the cupboard in the corner—top shelf. Here are his keys, all intact. I think this is the cupboard key."

Smith nodded.

"Come on, Petrie," he said. "We haven't a second to waste."

Our cab was waiting, and in a few seconds we were speeding along Wapping High Street. We had gone no more than a few hundred yards, I think, when Smith suddenly slapped his open hand down on his knee.

"That pigtail!" he cried. "I have left it behind! We must have it, Petrie! Stop! Stop!"

The cab was pulled up, and Smith alighted.

"Don't wait for me," he directed hurriedly. "Here, take Weymouth's card. Remember where he said the book was? It's all we want. Come straight on to Scotland Yard and meet me there."

"But Smith," I protested, "a few minutes can make no difference!"

"Can't it!" he snapped. "Do you suppose Fu-Manchu is going to leave evidence like that lying about? It's a thousand to one he has it already, but there is just a bare chance."

It was a new aspect of the situation and one that afforded no room for comment; and so lost in thought did I become that the cab was outside the house for which I was bound ere I realized that we had quitted the purlieus of Wapping. Yet I had had leisure to review the whole troop of events which had crowded my life since the return of Nayland Smith from Burma. Mentally, I had looked again upon the dead Sir Crichton Davey, and with Smith had waited in the dark for the dreadful thing that had killed him. Now, with those remorseless memories jostling in my mind, I was entering the house of Fu-Manchu's last victim, and the shadow of that giant evil seemed to be upon it like a palpable cloud.

Cadby's old landlady greeted me with a queer mixture of fear and embarrassment in her manner.

"I am Dr. Petrie," I said, "and I regret that I bring bad news respecting Mr. Cadby."

"Oh, sir!" she cried. "Don't tell me that anything has happened to him!" And divining something of the mission on which I was come, for such sad duty often falls to the lot of the medical man: "Oh, the poor, brave lad!"

Indeed, I respected the dead man's memory more than ever from that hour, since the sorrow of the worthy old soul was quite pathetic, and spoke eloquently for the unhappy cause of it.

"There was a terrible wailing at the back of the house last night, Doctor, and I heard it again to-night, a second before you knocked. Poor lad! It was the same when his mother died."

At the moment I paid little attention to her words, for such beliefs are common, unfortunately; but when she was sufficiently composed I went on to explain what I thought necessary. And now the old lady's embarrassment took precedence of her sorrow, and presently the truth came out:

"There's a—young lady—in his rooms, sir."

I started. This might mean little or might mean much.

"She came and waited for him last night, Doctor—from ten until half-past—and this morning again. She came the third time about an hour ago, and has been upstairs since."

"Do you know her, Mrs. Dolan?"

Mrs. Dolan grew embarrassed again.

"Well, Doctor," she said, wiping her eyes the while, "I DO. And God knows he was a good lad, and I like a mother to him; but she is not the girl I should have liked a son of mine to take up with."

At any other time, this would have been amusing; now, it might be serious. Mrs. Dolan's account of the wailing became suddenly significant, for perhaps it meant that one of Fu-Manchu's dacoit followers was watching the house, to give warning of any stranger's approach! Warning to whom? It was unlikely that I should forget the dark eyes of another of Fu-Manchu's servants. Was that lure of men even now in the house,