er 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."

"Would it not be advisable, Inspector," I asked excitedly, "to make
sure of her at once?"

Gatton smiled grimly, and:

"Marie would have to make herself invisible to evade Scotland Yard
now," he replied. "She is being watched closely. But," he continued,
"what do you make of these marks on the door?"

We had reclosed the garage door and now were standing immediately
inside. The marks to which my companion had drawn my attention were
situated high up near the roof.

"This may account for the statement of Bolton that the door seemed
more difficult to open last night than to-day," he said. "Unless I am
greatly mistaken, some sort of attachment existed here until quite
recently."

"Possibly a contrivance for reclosing the door?" I suggested.

The marks in fact roughly corresponded to those which would be made by
the presence of such a contrivance and there seemed to have been some
attempt where it had been removed to disguise the holes left by the
screws.

"But the purpose of it?" muttered Gatton helplessly.

"God knows," I said; "the purpose of the whole thing is a mystery
beyond me entirely."

"Assuming that such a piece of