“I can not understand it,” Gertrude said thoughtfully.  “I don’t think he knew Doctor Walker at all, and—­their relations could hardly have been cordial, under the circumstances.”

Jamieson pricked up his ears, and little by little he drew from us the unfortunate story of Halsey’s love affair, and the fact that Louise was going to marry Doctor Walker.

Mr. Jamieson listened attentively.

“There are some interesting developments here,” he said thoughtfully.  “The woman who claims to be the mother of Lucien Wallace has not come back.  Your nephew has apparently been spirited away.  There is an organized attempt being made to enter this house; in fact, it has been entered.  Witness the incident with the cook yesterday.  And I have a new piece of information.”

He looked carefully away from Gertrude.  “Mr. John Bailey is not at his Knickerbocker apartments, and I don’t know where he is.  It’s a hash, that’s what it is.  It’s a Chinese puzzle.  They won’t fit together, unless—­unless Mr. Bailey and your nephew have again—­”

And once again Gertrude surprised me.  “They are not together,” she said hotly.  “I—­know where Mr. Bailey is, and my brother is not with him.”

The detective turned and looked at her keenly.

“Miss Gertrude,” he said, “if you and Miss Louise would only tell me everything you know and surmise about this business, I should be able to do a great many things.  I believe I could find your brother, and I might be able to—­well, to do some other things.”  But Gertrude’s glance did not falter.

“Nothing that I know could help you to find Halsey,” she said stubbornly.  “I know absolutely as little of his disappearance as you do, and I can only say this:  I do not trust Doctor Walker.  I think he hated Halsey, and he would get rid of him if he could.”

“Perhaps you are right.  In fact, I had some such theory myself.  But Doctor Walker went out late last night to a serious case in Summitville, and is still there.  Burns traced him there.  We have made guarded inquiry at the Greenwood Club, and through the village.  There is absolutely nothing to go on but this.  On the embankment above the railroad, at the point where we found the machine, is a small house.  An old woman and a daughter, who is very lame, live there.  They say that they distinctly heard the shock when the Dragon Fly hit the car, and they went to the bottom of their garden and looked over.  The automobile was there; they could see the lights, and they thought someone had been injured.  It was very dark, but they could make out two figures, standing together.  The women were curious, and, leaving the fence, they went back and by a roundabout path down to the road.  When they got there the car was still standing, the headlight broken and the bonnet crushed, but there was no one to be seen.”

The detective went away immediately, and to Gertrude and me was left the woman’s part, to watch and wait.  By luncheon nothing had been found, and I was frantic.  I went up-stairs to Halsey’s room finally, from sheer inability to sit across from Gertrude any longer, and meet her terror-filled eyes.