THE THUMB-PRINT It was ten o'clock in the morning, and Whiteside and Tarling were sitting on a sofa in their shirt-sleeves, sipping their coffee.

Tarling was haggard and weary, in contrast to the dapper inspector of police.

Though the latter had been aroused from his bed in the early hours of the morning, he at least had enjoyed a good night's sleep.
They sat in the room in which Mrs.Rider had been murdered, and the rusty brown stains on the floor where Tarling had found her were eloquent of the tragedy.
They sat sipping their coffee, neither man talking, and they maintained this silence for several minutes, each man following his own train of thought.

Tarling for reasons of his own had not revealed his own adventure and he had told the other nothing of the mysterious individual (who he was, he pretty well guessed) whom he had chased through the grounds.
Presently Whiteside lit a cigarette and threw the match in the grate, and Tarling roused himself from his reverie with a jerk.
"What do you make of it ?" he asked.
Whiteside shook his head.
"If there had been property taken, it would have had a simple explanation.

But nothing has gone.