"She studied Earth. She knew the peculiarities of Earthmen."
"I assured her I had been outdoors today and that I was growing used to it."
"She may have known better."
Baley pounded fist against palm. "You're making her too clever. It doesn't fit and I don't believe it. In any case, no murder accusation can stick unless and until the absence of the murder weapon can be accounted for."
Daneel looked steadily at the Earthman, "I can do that, too, Partner Elijah."
Baley looked at his robot partner with a stunned expression. "How?"
"Your reasoning, you will remember, Partner Elijah, was this. Were Mrs. Delmarre the murderess, then the weapon, whatever it was, must have remained at the scene of the murder. The robots, appearing almost at once, saw no sign of such a weapon, hence it must have been removed from the scene, hence the murderer must have removed it, hence the murderer could not be Mrs. Delmarre. Is all that correct?"
"Correct."
"Yet," continued the robot, "there is one place where the robots did not look for the weapon."
"Where?"
"Under Mrs. Delmarre. She was lying in a faint, brought on by the excitement and passion of the moment, whether murderess or not, and the weapon, whatever it was, lay under her and out of sight."
Baley said, "Then the weapon would have been discovered as soon as she was moved."
"Exactly," said Daneel, "but she was not moved by the robots. She herself told us yesterday at dinner that Dr. Thool ordered the robots to put a pillow under her head and leave her. She was first moved by Dr. Altim Thool, himself, when he arrived to examine her."
"So?"
"It follows, therefore, Partner Elijah, that a new possibility arises. Mrs. Delmarre was the murderess, the weapon was at the scene of the crime, but Dr. Thool carried it off and disposed of it to protect Mrs. Delmarre."
Baley felt contemptuous. He had almost been seduced into expecting something reasonable. He said, "Completely motiveless. Why should Dr. Thool do such a thing?"
"For a very good reason. You remember Mrs. Delmarre's remarks concerning him: 'He always treated me since I was a child and was always so friendly and kind.' I wondered if he might have some motive for being particularly concerned about her. It was for that reason that I visited the baby farm and inspected the records. What I had merely guessed at as a possibility turned out to be the truth."
"What?"
"Dr. Altim Thool was the father of Gladia Delmarre, and what is more, he knew of the relationship."
Baley had no thought of disbelieving the robot. He felt only a deep chagrin that it had been Robot Daneel Olivaw and not himself that had carried through the necessary piece of logical analysis. Even so, it was not complete.
He said, "Have you spoken to Dr. Thool?"
"Yes. I have placed him under house arrest, also."
"What does he say?"
"He admits that he is the father of Mrs. Delmarre. I confronted him with the records of the fact and the records of his inquiries into her health when she was a youngster. As a doctor, he was allowed more leeway in this respect than another Solarian might have been allowed."
"Why should he have inquired into her health?"
"I have considered that, too, Partner Elijah. He was an old man when he was given special permission to have an additional child and, what is more, he succeeded in producing one. He considers this a tribute to his genes and to his physical fitness. He is prouder of the result, perhaps, than is quite customary on this world. Moreover, his position as physician, a profession little regarded on Solaria because it involves personal presences, made it the more important to him to nurture this sense of pride. For that reason, he maintained unobtrusive contact with his offspring."
"Does Gladia know anything of it?"
"As far as Dr. Thool is aware, Partner Elijah, she does not."
Baley said, "Does Thool admit removing the weapon?"
"No. That he does not."
"Then you've got nothing, Daneel."
"Nothing?"
"Unless you can find, the weapon and prove he took it, or at the very least induce him to confess, you have no evidence. A chain of deduction is pretty, but it isn't evidence."
"The man would scarcely confess without considerable questioning of a type I myself could not carry through. His daughter is dear to him."
"Not at all," said Baley. "His feeling for his daughter is not at all what you and I are accustomed to. Solaria is different!"
He strode the length of the room and back, letting himself cool. He said, "Daneel, you have worked out a perfect exercise in logic, but none of it is reasonable, just the same." (Logical but not reasonable. Wasn't that the definition of a robot?)
He went on, "Dr. Thool is an old man and past his best years, regardless of whether he was capable of siring a daughter thirty years or so ago. Even Spacers get senile. Picture him then examining his daughter in a faint and his son-in-law dead by violence. Can you imagine the unusual nature of the situation for him? Can you suppose he could have remained master of himself? So much the master of himself, in fact, as to carry out a series of amazing actions?
"Look! First, he would have had to notice a weapon under his daughter, one that must have been so well covered by her body that the robots never noticed it. Secondly, from whatever small scrap of object he noted, he must have deduced the presence of the weapon and seen at once that if he could but sneak off with that weapon, unseen, a murder accusation against his daughter would be hard to substantiate. That's pretty subtle thinking for an old man in a panic. Then, thirdly, he would have had to carry the plan through, also tough for an old man in a panic. And now, lastly, he would have to dare to compound the felony further by sticking to his lie. It all may be the result of logical thinking, but none of it is reasonable."