Baley caught that and said, “You’ll help me do so, Dr. Leebig. As a roboticist, you know that maneuvering robots into actions such as indirect murder takes enormous skill. I had occasion yesterday to try to put an individual under house arrest. I gave three robots detailed instructions intended to keep this individual safe. It was a simple thing, but I am a clumsy man with robots. There were loopholes in my instructions and my prisoner escaped.”

“Who was the prisoner?” demanded Attlebish.

“Beside the point,” said Baley impatiently. “What is the point is the fact that amateurs can’t handle robots well. And some Solarians may be pretty amateurish as Solarians go. For instance, what does Gladia Delmarre know about robotics?… Well, Dr. Leebig?”

“What?” The roboticist stared.

“You tried to teach Mrs. Delmarre robotics. What kind of a pupil was she? Did she learn anything?”

Leebig looked about uneasily. “She didn’t…” and stalled.

“She was completely hopeless, wasn’t she? Or would you prefer not to answer?”

Leebig said stiffly, “She might have pretended ignorance.”

“Are you prepared to say, as a roboticist, that you think Mrs. Delmarre is sufficiently skilled to drive robots to indirect murder?”

“How can I answer that?”

“Let me put it another way. Whoever tried to have me killed at the baby farm must have had to locate me by using interrobot communications. After all, I told no human where I was going and only the robots who conveyed me from point to point knew of my whereabouts. My partner, Daneel Olivaw, managed to trace me later in the day, but only with considerable difficulty. The murderer, on the other hand, must have done it easily, since, in addition to locating

me, he had to arrange for arrow poisoning and arrow shooting, all before I left the farm and moved on. Would Mrs. Delmarre have the skill to do that?”

Corwin Attlebish leaned forward. “Who do you suggest would have the necessary skill, Earthman?”

Baley said, “Dr. Jothan Leebig is self-admittedly the best robot man on the planet.”

“Is that an accusation?” cried Leebig.

“Yes!” shouted Baley.

The fury in Leebig’s eyes faded slowly. It was replaced not by calm, exactly, but by a kind of clamped-down tension. He said, “I studied the Delmarre robot after the murder. It had no detachable limbs. At least, they were detachable only in the usual sense of requiring special tools and expert handling. So the robot wasn’t the weapon used in killing Delmarre and you have no argument.”

Baley said, “Who else can vouch for the truth of your statement?”

“My word is not to be questioned.”

“It is here. I’m accusing you, and your unsupported word concerning the robot is valueless. If someone else will bear you out, that would be different. Incidentally, you disposed of that robot quickly. Why?”

“There was no reason to keep it. It was completely disorganized. It was useless.”

“Why?”

Leebig shook his finger at Baley and said violently, “You asked me that once before, Earthman, and I told you why. It had witnessed a murder which it had been powerless to stop.”

“And you told me that that always brought about complete collapse; that that was a universal rule. Yet when Gruer was poisoned, the robot that had presented him with the poisoned drink was harmed only to the extent of a limp and a lisp. It had actually itself been the agent of what looked like murder at the moment, and not merely a witness, and yet it retained enough sanity to be questioned.

“This robot, the robot in the Delmarre case, must therefore have been still more intimately concerned with murder than the Gruer robot. This Delmarre robot must have had its own arm used as the murder weapon.”

“All nonsense,” gasped out Leebig. “You know nothing about robotics.”

Baley said, “That’s as may be. But I will suggest that Security Head Attlebish impound the records of your robot factory and maintenance shop. Perhaps we can find out whether you have built robots with detachable limbs and, if so, whether any were sent to Dr. Delmarre, and, if so, when.”

“No one will tamper with my records,” cried Leebig.

“Why? If you have nothing to hide, why?”

“But why on Solaria should I want to kill Delmarre? Tell me that. What’s my motive?”

“I can think of two,” said Baley. “You were friendly with Mrs. Delmarre. Overly friendly. Solarians are human, after a fashion. You never consorted with women, but that didn’t keep you immune from, shall we say, animal urges. You saw Mrs. Delmarre—I beg your pardon, you viewed her—when she was dressed rather informally and—”

“No,” cried Leebig in agony.

And Gladia whispered energetically, “No.”

“Perhaps you didn’t recognize the nature of your feelings yourself,” said Baley, “or if you had a dim notion of it, you despised yourself for your weakness, and hated Mrs. Delmarre for inspiring it. And yet you might have hated Delmarre, too, for having her. You did ask Mrs. Delmarre to be your assistant. You compromised with your libido that far. She refused and your hatred was the keener for that. By killing Dr. Delmarre in such a way as to throw suspicion on Mrs. Delmarre, you could be avenged on both at once.”

“Who would believe that cheap, melodramatic filth?” demanded Leebig in a hoarse whisper. “Another Earthman, another animal, maybe. No Solarian.”

“I don’t depend on that motive,” said Baley. “I think it was there, unconsciously, but you had a plainer motive, too. Dr. Rikaine Delmarre was in the way of your plans, and had to be removed.”

“What plans?” demanded Leebig.

“Your plans aiming at the conquest of the Galaxy, Dr. Leebig,” said Baley.

“The earthman is mad,” cried Leebig, turning to the others. “Isn’t that obvious?”

Some stared at Leebig wordlessly, some at Baley.

Baley gave them no chance to come to decisions. He said, “You know better, Dr. Leebig. Dr. Delmarre was going to break off with you. Mrs. Delmarre thought it was because you wouldn’t marry. I don’t think so. Dr. Delmarre himself was planning a future in which ectogenesis would be possible and marriage unnecessary. But Dr. Delmarre was working with you; he would know, and guess, more about your work than anyone else. He would know if you were attempting dangerous experiments and he would try to stop you. He hinted about such matters to Agent Gruer, but gave no details, because he was not yet certain of the details. Obviously, you discovered his suspicions and killed him.”

“Mad!” said Leebig again. “I will have nothing more to do with this.”

But Attlebish interrupted. “Hear him out, Leebig!”

Baley bit his lip to keep from a premature display of satisfaction at the obvious lack of sympathy in the Security Head’s voice. He said, “In the same discussion with me in which you mentioned robots with detachable limbs, Dr. Leebig, you mentioned spaceships with built-in positronic brains. You were definitely talking too much then. Was it that you thought I was only an Earthman and incapable of understanding the implications of robotics? Or was it that you had just been threatened with personal presence, had the threat lifted, and were a little delirious with relief? In any case, Dr.

Quemot had already told me that the secret weapon of Solaria against the Outer Worlds was the positronic robot.”

Quemot, thus unexpectedly referred to, started violently, and cried, “I meant—”

“You meant it sociologically, I know. But it gives rise to thoughts. Consider a spaceship with a built-in positronic brain as compared to a manned spaceship. A manned spaceship could not use robots in active warfare. A robot could not destroy humans on enemy spaceships or on enemy worlds. It could not grasp the distinction between friendly humans and enemy humans.