There were a series of drops of blood, leading from the pool which had first attracted their attention, off into the dim distance at the side of the mighty building of the British Museum, which towered above them, like the ghost of some eastern castle.

“Follow this trail, Cunningham,” said Shelley; “though I haven’t much doubt of what we shall find at the end of it.”

“What do you mean, sir?” asked Cunningham in awestruck tones.

“Use your imagination, man,” snapped Shelley. “Anyhow, you’ll find out soon enough.”

The drops of blood grew scarcer as they walked along. But Shelley, stooping at intervals, found that they also grew definitely fresher, as if they had been dropped more recently. At one point there was again a little pool of blood. Someone had been badly wounded, that was obvious enough, and at this point he had doubtless paused to rest. The gruesome trail continued, however, and before long they arrived at the end of the road.

A man lay on his face before them. Sticking from his back was the hilt of a nasty-looking knife. Here was the source of the blood all right. Here was the man whose dreadful tracks they had been following around the forecourt of the British Museum. He was a tall man—over six feet in height—and his hair was iron-grey.

“What’s the meaning of this?” asked Cunningham in puzzled tones. He was, he admitted to himself, both perturbed and scared.

Shelley grinned. Again it was not a pleasant grin, but this time it spoke volumes of relief. Cunningham thought it curious that his chief should be almost pleased that yet another murder had been committed.

“Has this got anything to do with our case?” he asked.

Again Shelley grinned. “That, my dear Cunningham,” he said, indicating the body, “is our case.”

“You mean…?” Cunningham paused.

“I mean,” said Shelley, “that we have found the missing Dr. Crocker.”

It was almost with relief that Cunningham set about the details of practical work which the preliminary stages of any murder case involve. He telephoned to Scotland Yard for a doctor, for finger-print experts, and for photographers. He assisted Shelley in a rapid examination of the body. It was still warm. The man had been dead only for a few minutes at most—which was clear enough, in any case, from the fact that the blood had still been in a semi-liquid condition when they had found it.

Soon the police cars came swinging up, and the astonished caretaker had to open wide the main gates of the British Museum to admit them—the first time for many years that they had been opened at such an incredible hour. The forecourt filled with activity, and the body of Dr. Crocker was taken into the main museum building for the doctor to make his examination.

“Not much need for me this time, Shelley,” he said, when he had glanced at it.