Holding this conviction, the detective entered the room of the tragedy and
turned up the lights, all of them, so that he might see whatever was to be
seen. He walked back and forth examining the carpet, examining the walls,
examining the furniture, but paying little heed to the body. He went to the
open window and looked out, he went to the yellow sofa and sat down,
finally he shut off the lights and withdrew softly, closing the door behind
him. It was just as the commissary had said _with the exception of one
thing_.

When he returned to Number Seven, M. Paul found that Gritz had kept his
promise and sent him a pot of fragrant Turkish coffee, steaming hot, and a
box of the choicest Egyptian cigarettes. Ah, that was kind! This was
something like it! And, piling up cushions in the sofa corner, Coquenil
settled back comfortably to think and dream. This was the time he loved
best, these precious silent hours when the city slept and his mind became
most active--this was the time when chiefly he received those flashes of
inspiration or intuition that had so often and so wonderfully guided him.

For half an hour or so the detective smoked continuously and sipped the
powdered delight of Stamboul, his gaze moving about the room in friendly
scrutiny as if he would, by patience and good nature, persuade the walls
or, chairs to give up their secret. Presently he took off his glasses and,
leaning farther back against the cushions, closed his eyes in pleasant
meditation. Or was it a brief snatch of sleep? Whichever it was, a discreet
knock at the corridor door shortly ended it, and Papa Tignol entered to say
that he had finished the footprint molds.

M. Paul roused himself with an effort and, sitting up, his elbow resting
against the sofa back, motioned his associate to a chair.

"By the way," he asked, "what do you think of _that?_" He pointed to a
Japanese print in a black frame that hung near the massive sideboard.

"Why," stammered Tignol, "I--I don't think anything of it."

"A rather interesting picture," smiled the other. "I've been studying it."

"A purple sea, a blue moon, and a red fish--it looks crazy to me," muttered
the old _agent_.

Coquenil laughed at this candid judgment. "All the same, it has a bearing
on our investigations."

"_Diable!_"

M. Paul reached for his glasses, rubbed them deliberately and put them on.
"Papa Tignol," he said seriously, "I have come to a conclusion about this
crime, but I haven'