Standin’ on the back porch of the house are two of the help, so I judged.  One is a square-built female with a stupid, heavy face, while the other is a tall, skinny old girl with narrow-set eyes and a sharp nose.

“Well,” says I, “where’s your riot?”

“S-s-s-sh!” says he.  “They’re up to some mischief.  One of them is hiding something under her shawl.  Watch.”

Sure enough, the skinny one did have her left elbow stuck out, and there was a bulge in the shawl.

“Looks like a case of emptyin’ the ashes,” says I.

“Or of placing a bomb,” whispers the Lieutenant.

“Mooshwaw!” says I.  “Bomb your aunt!  What for should they—­”

“Look now!” he breaks in.  “There!”

They’re advancin’ in single file, slow and stealthy, and gazin’ around cautious.  Mainly they seem to be watchin’ the back fire-escapes of the flat buildin’ next door, but now and then one of ’em turns and glances towards the old house they’ve just left.  They make straight for the shack in the corner of the yard, and in a minute more the fat one has produced a key and is fumblin’ with the red padlock.

She opens the door only far enough to let the slim one slip in, then stands with her back against it, her eyes rollin’ first one way and then the other.

Two or three minutes the slim one was in there, then she slides out, the door is locked, and she scuttles off towards the house, the wide one waddlin’ behind her.

“My word!” gasps the Lieutenant.  “Right against the wing of your factory, that shed is.  And a bomb of that size would blow it into match-wood.”

“That’s so,” says I.

Course, we hadn’t really seen any bomb; but, what with the odd notions of them two females and the Lieutenant’s panicky talk, I was feelin’ almost jumpy myself.

“A time-fuse, most likely,” says he, “set for midnight.  That should give us several hours.  We must find out who lives in that house.”

“Ought to be simple,” says I.  “Come on.”

We chases around the block and rings up the janitor of the flat buildin’.  He’s a wrinkled, blear-eyed old pirate, just on his way to the corner with a tin growler.

“Yah!  You won’t git in to sell him no books,” says he, leerin’ at us.

“Think so?” says I, displayin’ a quarter temptin’.  “Maybe if we had his name, though, and knew something about him, we might—­”

“It’s Bauer,” says the janitor, eyein’ the two bits longin’.  “Herman Z. Bauer; a big brewer once, but now—­yah, an old cripple.  Gout, they say.  And mean as he is rich.  See that high fence?  He built that to shut off our light—­the swine!  Bauer, his name is.  You ask for Herman Bauer.  Maybe you get in.”

“Thanks, old sport,” says I, slippin’ him the quarter.  “Give him your best regards, shall I?”

And as he goes off chucklin’ the Lieutenant whispers hoarse: