k in less than
an hour. "Come," he said, "Plummer is below, and we are going next door,
to Denson's office. I've an idea that we may get at something at last.
The police are after Samuel hot-foot. They think he should be made sure
of in any case without delay; and I must say they have some reason, on
the face of it."

We joined Plummer at once--I have already spoken of Plummer in my
accounts of several of Hewitt's cases in which I met him--and we all
turned into the office next door. There we found a very frightened and
bewildered office boy, whom Denson had given a holiday yesterday, after
sending him down to Samuel. He had come to his work as usual, only to
meet the housekeeper's tale of the murder of his master and the end of
his business prospects. He had little or no information to impart. He
had only been employed for a month or six weeks, and during that time
his work had been practically nothing.

Plummer nodded at this information, and sniffed comprehensively at the
office furniture. "I know this sort o' stuff," he said. "This is the way
they fit up long firm offices and such. This place was taken for the
job, that's plain, by one or both of 'em."

The boy's address was taken, and he was given a final holiday, and asked
to send up the housekeeper as he went out. Plummer passed Hewitt a bunch
of keys.

The housekeeper entered. "Now, Hutt," said Martin Hewitt, "you were
saying yesterday, I think, that the main front door was the only
entrance and exit for this building?"

"That's so, sir--the only one as anybody can use, except me."

"Oh! then there _is_ another, then?"

"Well, not exactly to say an entrance, sir. There's a small private door
at the back into the court behind, but that's only opened to take in
coals and such, and I always have the key. This house isn't like yours,
sir; you have no back way into the court as we have. It's a convenience,
sometimes."

"Ah, I've no doubt. Do you happen to have the key with you?"

"It's on the bunch hanging up in my box, sir. Shall I fetch it?"

"I should like to see it, if you will."

The housekeeper disappeared, and presently returned with a large bunch
of keys.

"This is the one, Mr. Hewitt," he explained, lifting it from among the
rest.

Hewitt examined it closely, and then placed beside it one from the bunch
Plummer had given him. "It seems you're not the only person who ever had
a key exactly like that, Hutt," he said. "See here--this was found