From "Manual of Muad'Dib" by the Princess Irulan

A silky voice, that one. That was Piter .
"So I see, Piter."
A rumbling basso: the Baron .
Leto sensed increasing definition in his surroundings. The chair beneath him took on firmness, the bindings were sharper.
And he saw the Baron clearly now. Leto watched the movements of the man's hands: compulsive touchings—the edge of a plate, the handle of a spoon, a finger tracing the fold of a jowl.
Leto watched the moving hand, fascinated by it.
"You can hear me, Duke Leto," the Baron said. "I know you can hear me. We want to know from you where to find your concubine and the child you sired on her."
No sign escaped Leto, but the words were a wash of calmness through him. It's true, then: they don't have Paul and Jessica .
"This is not a child's game we play," the Baron rumbled. "You must know that." He leaned toward Leto, studying the face. It pained the Baron that this could not be handled privately, just between the two of them. To have others see royalty in such straits—it set a bad precedent.
Leto could feel strength returning. And now, the memory of the false tooth stood out in his mind like a steeple in a flat landscape. The nerve-shaped capsule within that tooth—the poison gas—he remembered who had put the deadly weapon in his mouth.
Yueh .
Drug-fogged memory of seeing a limp corpse dragged past him in this room hung like a vapor in Leto's mind. He knew it had been Yueh.
"Do you hear that noise, Duke Leto?" the Baron asked.
Leto grew conscious of a frog sound, the burred mewling of someone's agony.
"We caught one of your men disguised as a Fremen, " the Baron said. "We penetrated the disguise quite easily: the eyes, you know. He insists he was sent among the Fremen to spy on them. I've lived for a time on this planet, cher cousin. One does not spy on those ragged scum of the desert. Tell me, did you buy their help? Did you send your woman and son to them?"
Leto felt fear tighten his chest. If Yueh sent them to the desert fold . . . the search won't stop until they 're found .
"Come, come," the Baron said. "We don't have much time and pain is quick. Please don't bring it to this, my dear Duke." The Baron looked up at Piter who stood at Leto's shoulder. "Piter doesn't have all his tools here, but I'm sure he could improvise."
"Improvisation is sometimes the best, Baron."
That silky, insinuating voice! Leto heard it at his ear.
"You had an emergency plan," the Baron said. "Where have your woman and the boy been sent?" He looked at Leto's hand. "Your ring is missing. Does the boy have it?"
The Baron looked up, stared into Leto's eyes.
"You don't answer," he said. "Will you force me to do a thing I do not want to do? Piter will use simple, direct methods. I agree they're sometimes the best, but it's not good that you should be subjected to such things."
"Hot tallow on the back, perhaps, or on the eyelids," Piter said. "Perhaps on other portions of the body. It's especially effective when the subject doesn't know where the tallow will fall next. It's a good method and there's a sort of beauty in the pattern of pus-white blisters on naked skin, eh, Baron?"
"Exquisite," the Baron said, and his voice sounded sour.
Those touching fingers! Leto watched the fat hands, the glittering jewels on baby-fat hands—their compulsive wandering.
The sounds of agony coming through the door behind him gnawed at the Duke's nerves. Who is it they caught? he wondered. Could it have been Idaho ?
"Believe me, cher cousin," the Baron said. "I do not want it to come to this."
"You think of nerve couriers racing to summon help that cannot come," Piter said. "There's an artistry in this, you know."
"You're a superb artist," the Baron growled. "Now, have the decency to be silent."
Leto suddenly recalled a thing Gurney Halleck had said once, seeing a picture of the Baron: " 'And I stood upon the sand of the sea and saw a beast rise up out of the sea . . . and upon his heads the name of blasphemy .' "
"We waste time, Baron," Piter said.
"Perhaps." The Baron nodded. "You know, my dear Leto, you'll tell us in the end where they are. There's a level of pain that'll buy you."