“Are you in the habit, sir,”—the detective turned to Robin now,—“of going out for walks in the dark?”

Greve shrugged his shoulders.

“I had been sitting in the billiard-room. It was rather stuffy, so I thought I’d like some air before tea!”

“You left Miss Trevert in the billiard-room?”

“Yes!”

“Why?”

Greve put a hand to his throat and eased his collar.

“The gong had sounded for tea,” the detective went on imperturbably; “surely it would have been more natural for you to have brought Miss Trevert with you?”

“I didn’t wish to!”

Mr. Manderton cleared his throat.