son's face.

"Of course he can't get away. See if there's anything on his clothes,
Rawlins. He ought to have the hatpin. Then let him go."

The detective, however, failed to find the hatpin or any other weapon.

"You see," Paredes smiled. "That's something in my favour."

He stepped back, brushing his clothing with his uninjured hand. He
lighted a cigarette. He drew back the coat sleeve of his left arm and
readjusted the bandage. He glanced up as heavy footsteps heralded
Doctor Groom.

"Hello, Doctor," he called cheerily. "I was afraid you'd nap through the
show. It seems the bloodhounds of the law left us out of their
confidence."

"What's all this?" the doctor rumbled.

Paredes waved his hand.

"I am a prisoner."

The doctor gaped.

"You mean you--"

"Young Blackburn caught him," Robinson explained. "He was in a position
to finish him just as he did Howells."

"Except that I had no hatpin," Paredes yawned.

The doctor's uneasy glance sought the opening in the wall.

"I thought you had examined all these walls," he grumbled. "How did you
miss this?"

Robinson ran his fingers through his hair.

"That's what I've been asking myself," he said. "I went over that
panelling a dozen times myself."

Bobby and Katherine went closer. Bobby had been from the first puzzled by
Paredes's easy manner. He had a quick hope. He saw the man watch with an
amused tolerance while the district attorney bent over, examining the
face of the panel.

"An entire section," Robinson said--"the thickness of the wall--has been
shifted to one side. No wonder we didn't see any joints or get a hollow
sound from this panel any more than from the others. But why didn't we
stumble on the mechanism? Maybe you'll tell us that, Paredes."

The Panamanian blew a wreath of smoke against the ancient wall.

"Gladly, but you will find it humiliating. I have experienced humility in
this hall myself. The reason you didn't find any mechanism is that there
wasn't any. You looked for something most cautiously concealed, not
realizing that the best concealment is no concealment at all. It's
fundamental. I don't know how it slipped my own mind. No grooves show
because the door is an entire panel. There isn't even a latch. You merely
push hard against its face. Such arrangements are common enough in
colonial houses, and there was more than the nature of the crimes to tell
you there was some such thing here. I mean if you will examine the
farther