“You mean the pseudo-Derek, I suppose? Yes, he's gone to ground”—Cargill's expression showed a relief which was quenched as Sir Clinton continued—“in the same place as you put Paul Fordingbridge.”

Cargill's head sank at the news.

“I'm afraid I can't stay,” Sir Clinton said, with almost ironical politeness. “You've given me such a lot of work to do, you know, lately. I shan't trouble you with questions, because I think we shall get all we want from your confederates. If you need anything we can give you, please ask the constables for it. Good evening.”

In the corridor, Wendover broke into a flood of questions; but Sir Clinton brushed them aside.

“There's time enough for that by and by,” he said brusquely. “I must get to the bottom of this business first. We'll go along and ask if Mrs. Fleetwood can see us for a moment or two.”

Wendover was glad to find, when they entered the Fleetwood suite, that Cressida seemed to be getting over the worst of the shock. Her face lighted up as she saw them come in, and she began at once to thank them. Sir Clinton brushed the thanks aside.

“There's nothing in it,” he said. “I only wish we'd been sooner.”

At the words, Cressida's expression changed, as though some dreadful thing had been recalled to her. Sir Clinton put his hand into his pocket and drew out the glass syringe.

“What part did this thing play?” he asked gently.

The sight of it brought back all Cressida's terrors.