"This is where the mystery centers," said Gatton.

I made no reply, for I had not yet recovered from the shock of that
discovery in the deserted supper room. It was so wholly unexpected and
yet it so cruelly confirmed the Inspector's undisguised suspicions
that it seemed to me to have created a sort of impalpable barrier
between us. Of this Gatton was evidently conscious. He endeavored to
arouse my interest in the inquiries which he was conducting in the
garage, but for long enough I saw nothing of the place in which we
stood; I could only see that photograph smiling at me inquiringly
through a haze of doubt, and my companion's words reached me in a
muffled fashion. Finally, however, I succeeded in rousing myself from
this dazed condition, and confident as ever that Isobel was innocent
of all complicity in the matter:

"The presence of the photograph," I said, "takes us a step further.
Don't you see, Inspector, that this is a deeply and cunningly laid
trap? What I had taken for a series of unfortunate coincidences I
perceive now to be the workings of an elaborate scheme involving
perfectly innocent people in the crime."

"H'm," said Gatton doubtfully; "it may be as you suggest; at any rate
it is a new point of view and one which I confess had not occurred to
me. There is one witness who can clear up any doubt on the subject."

"You mean Marie?"

"Exactly. She will lie, beyond doubt, but we shall find means to reach
the truth."