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

Is my Leto dead, then? Jessica asked herself. She felt a silent wail begin somewhere in her mind.
The Baron kept his attention on the Mentat. "Understand yourself, Piter. You want her because she was a Duke's woman, a symbol of his power—beautiful, useful, exquisitely trained for her role. But an entire duchy, Piter! That's more than a symbol; that's the reality. With it you could have many women . . . and more."
"You do not joke with Piter?"
The Baron turned with that dancing lightness the suspensors gave him. "Joke? I? Remember—I am giving up the boy. You heard what the traitor said about the lad's training. They are alike, this mother and son—deadly." The Baron smiled. "I must go now. I will send in the guard I've reserved for this moment. He's stone deaf. His orders will be to convey you on the first leg of your journey into exile. He will subdue this woman if he sees her gain control of you. He'll not permit you to untie her gag until you're off Arrakis. If you choose not to leave . . . he has other orders."
"You don't have to leave," Piter said. "I've chosen."
"Ah, hah!" the Baron chortled. "Such quick decision can mean only one thing."
"I will take the duchy," Piter said.
And Jessica thought: Doesn't Piter know the Baron's lying to him? But—how could he know? He's a twisted Mentat .
The Baron glanced down at Jessica. "Is it not wonderful that I know Piter so well? I wagered with my Master at Arms that this would be Piter's choice. Hah! Well, I leave now. This is much better. Ah-h, much better. You understand, Lady Jessica? I hold no rancor toward you. It's a necessity. Much better this way. Yes. And I've not actually ordered you destroyed. When it's asked of me what happened to you, I can shrug it off in all truth."
"You leave it to me then?" Piter asked.
"The guard I send you will take your orders," the Baron said. "Whatever's done I leave to you." He stared at Piter. "Yes. There will be no blood on my hands here. It's your decision. Yes. I know nothing of it. You will wait until I've gone before doing whatever you must do. Yes. Well . . . ah, yes. Yes. Good."
He fears the questioning of a Truthsayer , Jessica thought. Who? Ah-h-h, the Reverend Mother Gaius Helen, of course! If he knows he must face her questions, then the Emperor is in on this for sure. Ah-h-h-h, my poor Leto .
With one last glance at Jessica, the Baron turned, went out the door. She followed him with her eyes, thinking: It's as the Reverend Mother warned—too potent an adversary .
Two Harkonnen troopers entered. Another, his face a scarred mask, followed and stood in the doorway with drawn lasgun.
The deaf one , Jessica thought, studying the scarred face. The Baron knows I could use the Voice on any other man .
Scarface looked at Piter. "We've the boy on a litter outside. What are your orders?"
Piter spoke to Jessica. "I'd thought of binding you by a threat held over your son, but I begin to see that would not have worked, I let emotion cloud reason. Bad policy for a Mentat." He looked at the first pair of troopers, turning so the deaf one could read his lips: "Take them into the desert as the traitor suggested for the boy. His plan is a good one. The worms will destroy all evidence. Their bodies must never be found."
"You don't wish to dispatch them yourself?" Scarface asked.
He reads lips , Jessica thought.
"I follow my Baron's example," Piter said. "Take them where the traitor said."
Jessica heard the harsh Mentat control in Piter's voice, thought: He, too, fears the Truthsayer .
Piter shrugged, turned, and went through the doorway. He hesitated there, and Jessica thought he might turn back for a last look at her, but he went out without turning.
"Me, I wouldn't like the thought of facing that Truthsayer after this night's work," Scarface said.
"You ain't likely ever to run into that old witch," one of the other troopers said. He went around to Jessica's head, bent over her. "It ain't getting our work done standing around here chattering. Take her feet and—"
"Why'n't we kill 'em here?" Scarface asked.
"Too messy," the first one said. "Unless you wants to strangle'em. Me, I likes a nice straightforward job. Drop 'em on the desert like that traitor said, cut 'em once or twice, leave 'the evidence for the worms. Nothing to clean up afterwards."
"Yeah . . . well, I guess you're right," Scarface said.
Jessica listened to them, watching, registering. But the gag blocked her Voice, and there was the deaf one to consider.
Scarface holstered his lasgun, took her feet. They lifted her like a sack of grain, maneuvered her through the door and dumped her onto a suspensor-buoyed litter with another bound figure. As they turned her, fitting her to the litter, she saw her companion's face—Paul! He was bound, but not gagged. His face was no more than ten centimeters from hers, eyes closed, his breathing even.