by which it could have been accomplished. This time he added the attempt on his own life at the baby farm.
Leebig said impatiently, "I suppose that was managed by having one robot poison an arrow without knowing it was using poison, and having a second robot hand the poisoned arrow to the boy after telling him that you were an Earthman, without its knowing that the arrow was poisoned."
"Something like that. Both robots would be completely instructed."
"Very farfetched," said Leebig.
Quemot was pale and looked as though he might be sick at any moment. "No Solarian could possibly use robots to harm a human."
"Maybe so," said Baley with a shrug, "but the point is that robots can be so manipulated. Ask Dr. Leebig. He is the roboticist."
Leebig said, "It does not apply to the murder of Dr. Delmarre. I told you that yesterday. How can anyone arrange to have a robot smash a man's skull?"
"Shall I explain how?"
"Do so if you can."
Baley said, "It was a new-model robot that Dr. Delmarre was testing. The significance of that wasn't plain to me until last evening, when I had occasion to say to a robot, in asking for his help in rising out of a chair, 'Give me a hand!' The robot looked at his own hand in confusion as though he thought he was expected to detach it and give it to me. I had to repeat my order less idiomatically. But it reminded me of something Dr. Leebig had told me earlier that day. There was experimentation among robots with replaceable limbs.
"Suppose this robot that Dr. Delmarre had been testing was one such, capable of using any of a number of interchangeable limbs of various shapes for different kinds of specialized tasks. Suppose the murderer knew this and suddenly said to the robot, 'Give me your arm.' The robot would detach its arm and give it to him. The detached arm would make a splendid weapon. With Dr. Delmarre dead, it could be snapped back into place."
Stunned horror gave way to a babble of objection as Baley talked. His last sentence had to be shouted, and, even so, was all but drowned Out.
Attlebish, face flushed, raised himself from his chair and stepped forward. "Even if what you say is so, then Mrs. Delmarre is the murderess. She was there, she quarreled with him, she would be watching her husband working with the robot, and would know of the replaceable-limb situation - which I don't believe, by the way. No matter what you do, Earthman, everything points to her."
Gladia began to weep softly.
Baley did not look at her. He said, "On the contrary, it is easy to show that, whoever committed the murder, Mrs. Delmarre did not.
Jothan Leebig suddenly folded his arms and allowed an expression of contempt to settle on his face.
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."