“What’s wrong?” French demanded.

“He’s gone off,” was the unwilling reply. “I guess that chap’s given us the slip.”

“Speak up,” French insisted.

“The only place,” the man went on, “we hadn’t our eyes glued on, was the front door. He must have come out through that. There’s been a motor truck with one or two queer-looking chaps in it, at the corner of the avenue there for the last ten minutes. I’d just made up my mind to stroll round and see what it was up to when Jim, who was on the other side, shouted out. A man jumped up into it and they made off at once.”

“Could he have come from this house?” French asked sternly.

“I guess, if he’d come out from the front door, he might just have done it,” the man admitted.

Quest and the Inspector exchanged glances.

“He’s done us!” Quest muttered,—“done us like a couple of greenhorns!”

The Inspector’s rubicund countenance was white with fury. His head kept turning in the direction of Laura, to whom the Professor was busy rendering first aid.

“If I never take another job on as long as I live,” he declared, “I’ll have that fellow before I’m through!”