f what I've suspected for some time--that
Mortimer is the quadrangle thief!"

"You don't say so! How do you figure it out?"

"Just think and you'll see it for yourself," went on Andy. "When we had
the chase after the thief down this corridor that time, the trail seemed
to lead right to this closet, didn't it?"

"Sure," agreed Dunk.

"And who did we find in there?"

"Why, Mort, of course. But he said he was looking for Charley Taylor's
bat."

"Well, he may have been, but that was only an excuse. Mortimer didn't
want that bat, but he was almost caught and he did want a place to hide
the stuff. The book he could slip in his pocket, but he couldn't do that
with the cup. So he threw it back in a corner, and it's been there ever
since. Probably he was afraid to come for it."

"Andy, I believe you're right!" cried Dunk. "But one thing more--did you
find a pair of rubber shoes? You know Frank said the fellow that went
out of his room in such a hurry wore rubber shoes."

"I forgot about that. I'll have another look."

"I'll go with you. Ikey was here and I paid him for your socks and mine.
So we can lock up."

"And be sure you do lock," warned Andy. "I don't want to lose any more
stuff. Say, Mortimer must have my sleeve links, all right."

"All wrong, you mean. And my watch, too! I wonder if we're on the verge
of a discovery?"

"It looks so," said Andy, grimly.

Quickly and silently they went to the storeroom. They were not
disturbed, for there were several class dinners on that night, and most
of the occupants of Wright Hall were out. Andy and Dunk intended going
later.

They rummaged in the closet and, when about to give up, not having found
what they sought, Andy unearthed a pair of rubbers.

"These might be what the fellow wore," said Dunk, as he looked at them.
"He could easily have slipped them off. See if there are any marks
inside."

Andy looked and uttered a startled cry. For there, on the inner canvas
of the rubber, printed in ink, were the initials "M. G."

"They're his, all right!" spoke Andy, in a low tone.

"Then he's the quadrangle thief," went on Dunk. "Come on back to our
room, and we'll talk this over. Something's has got to be done."

"That's right," agreed Andy. "But what?"

"We must set a trap," suggested Dunk.

"A trap?"

"Yes, do something to catch this mean thief--Mortimer or whoever he
is--in the act."

"Hadn't we better tell the Dean--or someone."

"No," said Dunk, after