“That’ll about do to go on with,” said Inspector Chippenfield, with a sudden change of tone, rising to his feet as he spoke.  “Rolfe, keep an eye on her while I search the flat.”

Rolfe crossed over from where he had been sitting and stood beside the girl.  She glanced up at him wildly, with terror dawning in the depths of her dark eyes.

“What do you mean?  How dare you?” she cried, in an effort to be indignant.

“Now, don’t try your tragedy airs on us,” said the inspector.  “We’ve no time for them.  If you won’t tell the truth you had better say nothing at all.”  He plunged his hand into a jardiniere and withdrew a briar-wood pipe.  “This looks to me like Birchill’s property.  Keep that dog back, Rolfe.”

The little dog had sprung off his cushion and was eagerly following the inspector out of the room.  Rolfe caught up the animal in his arms, and returned to where the girl was sitting.  Her face was white and strained, and her big dark eyes followed Inspector Chippenfield, but she did not speak.  The inspector tramped noisily into the little hall, leaving the door of the room wide open.  Rolfe and the girl saw him fling open the door of another room—­a bedroom—­and stride into it.  He came out again shortly, and went down the hall to the rear of the flat.  A few minutes later he came back to the room where he had left Rolfe and the girl.  His knees were dusty, and some feathers were adhering to his jacket, as though he had been plunging in odd nooks and corners, and beneath beds.  He was hot, flurried, and out of temper.

“The bird’s flown!” were his first words, addressed to Rolfe.  “I’ve hunted high and low, but I cannot find a sign of him.  It beats me how he’s managed it.  He couldn’t have gone out the front way without my seeing him go past the door, and the back windows are four stories high from the ground.”

“Perhaps he wasn’t here when we came in,” suggested Rolfe.

“Oh, yes, he was.  Why, he’d been smoking that pipe in this very room.  She was clever enough to open the window to let out the tobacco smoke before she let us in, but she didn’t hide the pipe properly, for I saw the smoke from it coming out of the jardiniere, and when I put my hand on the bowl it was hot.  Feel it now.”

Rolfe placed his hand on the pipe, which Inspector Chippenfield had deposited on the table.  The bowl was still warm, indicating that the pipe had recently been alight.

“He must have been smoking the pipe when we knocked at the door, and dashed away to hide before she let us in,” grumbled the inspector.  “But the question is—­where can he have got to?  I’ve hunted everywhere, and there’s no way out except by the front door, so far as I can see.  Go and have a look yourself, Rolfe, and see if you can find a trace of him.  I’ll watch the girl.”