to help me. We found no signs of violence upon it. I was hoping
that if Mr. Douglas defended himself with the hammer, he might
have left his mark upon the murderer before he dropped it on the
mat. But there was no stain."

"That, of course, proves nothing at all," remarked Inspector
MacDonald. "There has been many a hammer murder and no trace on
the hammer."

"Quite so. It doesn't prove it wasn't used. But there might
have been stains, and that would have helped us. As a matter of
fact there were none. Then I examined the gun. They were
buckshot cartridges, and, as Sergeant Wilson pointed out, the
triggers were wired together so that, if you pulled on the hinder
one, both barrels were discharged. Whoever fixed that up had
made up his mind that he was going to take no chances of missing
his man. The sawed gun was not more than two foot long--one
could carry it easily under one's coat. There was no complete
maker's name; but the printed letters P-E-N were on the fluting
between the barrels, and the rest of the name had been cut off by
the saw."

"A big P with a flourish above it, E and N smaller?" asked
Holmes.

"Exactly."

"Pennsylvania Small Arms Company--well-known American firm," said
Holmes.