ers of Mr. Flynn's friends. He seemed to know all about
it."

"You say it was about three minutes after they went into the
house?"

"It could not have been more than five minutes at most."

"Did you notice anybody on this street when you came, or before
the explosion?"

"No, sir. We made a search afterward. You see the next five houses
are closed for the summer. That means that the nearest house where
there was anybody at the time is not less than three hundred yards
away. There wasn't a soul on this street. After the explosion, of
course, there was a mob. You'd wonder where all the people came
from in such a small town Sunday evening."

"And the three men in the house were killed outright?"

"Yes, sir."

"Did you look in the patch of woods over there?"

"No, sir. I didn't see the need for it and I was too busy keeping
the people a safe distance away. Fortunately there was no fire."

Professor Brierly went into what was left of the house. He
carefully picked his way through the broken furniture, the
crumbling brick and mortar, twisted metal. Frank Hall, from the
Bureau of Combustibles, was there. He was acquainted with
Professor Brierly and he greeted the old scientist cordially,
saying:

"There is some evidence, Professor, of a simple bomb filled with
black powder. I cannot find the firing device, whatever it was. I
cannot find any timing device either."

"A timing device, Mr. Hall? Suppose the explosion had occurred ten
minutes earlier. It happened, if I am correctly informed, only
three minutes after he came home."

"That's all right, Professor. I thought of that, but he was
expected much sooner, hours sooner."

Professor Brierly nodded absently. "I see," he murmured. He was
looking about him intently. Suddenly he stooped and peered at a
black mark along a strip of moulding that had fallen from some
part of the wrecked structure. He picked it up and examined it
carefully. He showed it to Mr. Hall.

"Did you see this, Mr. Hall? Looks like a burn that might have
been made by a fuse, does it not?"

"Yes, Professor, it does, but one of the peculiarities about this
kind of thing is that it destroys its own evidence pretty much. If
we don't know where the lighted fuse originated and where it led,
it doesn't do us much good, does it?"

"That's right, but this obviously comes from an upper room,
doesn't it?"

"Yes, I believe it does. But the upper rooms are gone, you see."

"And you really think, d