"Not necessarily. Perhaps to steal, or lie. I can imagine a hundred different situations where a thieving robot could be valuable. All I'm saying is that this sort of thing may be rare-but not unheard of."

"But why would Teddy be programmed to kill? Who would have been able to do it? And who would have reason?" Jubal asked.

St. Cyr said, "I'll get to that in a moment. First, though, I feel as if I ought to explain why I took so long reaching the conclusions that I have. I had all the facts for some time, but I just could not make them mesh."

"No need to explain, surely," Hirschel interjected. "No one would suspect a master unit robot of murder-not any more than anyone would suspect a man of giving himself a severe beating and then reporting it to the local authorities."

St. Cyr licked his lips and waited for the other half of his symbiote to respond subvocally. When it did not, he said, "It was worse than that for me, though. You know that my reasoning powers are augmented by the data banks and logic circuitry in the bio-computer sh.e.l.l that taps my nervous system. In those data banks are the iron-worded Laws of Robotics. Even when I began to wonder about Teddy, the bio-computer half of the symbiosis had such a strong effect on me that I almost willingly disregarded the prospect without following up on it as I should have. The bio-computer very nearly convinced me that it was a silly supposition-impossible, an emotional reaction. But what the bio-computer could never come to terms with-since it is not human and has no conception of human fallibility- was the limited knowledge of those who had fed its data into it in the first place. Programmed knowledge, to any computer, is the word of G.o.d. All judgments are based on it. In this case, no one had informed the other half of my symbiote that there was a way around the Laws of Robotics."

"Okay," Jubal said. "I understand that, and I can't blame you for anything, certainly. But what about the proof you mentioned?"

"First of all," St. Cyr said, "the fact that the killer left no footprints in the damp garden soil can be explained by the fact that Teddy has a gravplate mobility system and never touches the ground. The lack of fingerprints is easily accounted for; stainless steel fingers are not whorled."

"But this is not conclusive," Hirschel said.

"Also, consider that he has access to the house, everywhere in the house. He can override the voice locks on all the bedroom doors, enter silently and at will. And, in those cases where the victims were murdered on their balconies, it is possible that he could increase the power input on the gravplate generators and drift up the side of the house to attack them without ever entering their rooms. He could get very close to anyone, for he was uniformly trusted."

Everyone but Tina and Hirschel seemed too stunned to take it all in. One trusted one's mechanical servants, for they were incapable of doing anything to make that trust hollow. If one could not trust robots, then all of modern society came in for suspicion. If robots could turn against men, all the underpinnings of this life might be as shaky as rotted planks. Hirschel was less affected because he was more the primitive than any of them. If the entire fabric of human existence, across the hundreds of settled worlds in the galaxy, fell apart tomorrow from some unimaginable cosmic event, he would survive with just his hands and a knife. Tina also, though a child of civilization, was not so affected by the disclosure as the others were-perhaps because she had ceased to care about a lot of things.

"How did he get the corpses to look as if they'd been clawed by an animal?" Hirschel asked. "His fingers are blunt, not sharp."

St. Cyr lifted the paper sack onto his lap, opened the top and lifted out a long tool that looked very much like a back-scratcher, with a long shaft terminating in four hideously sharpened tines that were curved at the tips like well-honed claws. "As you know, the 'hands' at the ends of Teddy's arms are only attachments which are removable so that he can accommodate the insertion of various other tools. The ends of his arms are something like drill clamps that will take any number of bits. This set of claws is one of those 'bits.'"

"Where in h.e.l.l did he get that?" Jubal asked.

"He made it," St. Cyr said. "He's perfectly capable of operating a machine shop-just as you ordered him-a function he usually performs in order to transfer your silver designs from paper to reality. Somewhere along the line he took the time to make himself this dandy little ripper."

"What I'd like to know is where you you got that," Hirschel said. got that," Hirschel said.

"In Teddy's workshop."

"Just a while ago?"

"Yes."

"And he doesn't know what you went down there for?" Hirschel clearly felt St. Cyr had made a serious tactical error.

"He doesn't even know I went down there," St. Cyr said. "I told him I was going to the fourth floor. I sent the elevator up there, empty. Since there was no one else in the house to use it just then-you were all in the kitchen-I knew I had the elevator shaft to myself. I just used it to go down one floor to the garage, then into the workshop."

"With that arm?" Hirschel asked.

"The arm wasn't any problem going down," the cyberdetective said. "Coming up was a real b.i.t.c.h, though."

Hirschel smiled admiringly and said, "I believe that I have been underestimating you all along."

St. Cyr acknowledged the compliment with a nod, though it pleased him very much. On his left, Tina moved closer to him, until he felt their hips brush.

Hirschel said, "I expect that you can explain where he got that narcotic-dart gun that he used against you in the garden."

The detective reached into the paper sack, removed a pistol and handed it to the hunter. "Recognize the make?"

Hirschel gave it a careful scrutiny, pulled back the slide and peered at as much of the workings as he could see. "Very simplistic, but well-made. The mechanisms look too fragile to last long."

"Teddy machined it," St. Cyr said.

Jubal spoke up again: "But it was never stipulated that he know weaponry. I wouldn't want a master unit of mine to have that kind of knowledge."

"You never stipulated that he kill your sons and daughters, either," St. Cyr said.

Hirschel handed the gun back, and the detective put it with the artificial claws. To Hirschel, he said, "There is a wolfs head mounted in your suite. I saw it the first day I was here."

"I killed it a good many years ago," Hirschel said. "Before the species was eradicated by Climicon."

"Was that the only one you shot?"

"No. There were two others. But I didn't see any sense in having them mounted."

"What was done with them?" He already knew the general answer to that, but he wanted to get everything as exact as he could.

"I gutted, cured and tanned the hides, left the heads intact except for the eyes. I knew the species was slated for eradication, and I knew that the hides would be worth a great deal of money some day, for museums and such. I have a lot of animal skins stored here on the second level. It's another eccentricity that Jubal allows me." He smiled at Jubal, and St. Cyr thought there was genuine affection on the older man's part for the younger.

The cyberdetective pulled the last item from the paper bag. It was one of the wolf hides that Hirschel had prepared and stored. "Teddy used it to plant wolf hairs with the bodies-and as a partial disguise when he attacked me in the gardens. He was wise enough to realize that if I were hallucinating, this minimal diversion would confuse me enough to keep me from recognizing him. He was also clever enough to disguise himself at all, on the chance that he might fail to kill me then-as he did."

"But," Jubal said, "what about the TDX-4, the drug he used on you? He could destroy all of this when he had finished with all of us-but the house computer would keep a record of the drug purchase. The police, if they were clever enough, could figure him out on the basis of that-and find out who illegally programmed him to kill."

"Except that Teddy didn't buy the hallucinogenic drug. It was already here, in the house."

"Where?" the patriarch asked. "No one in this house uses hallucinogens." He spoke with smug authority.

"I use them," Alicia said. She said so little, spoke so seldom, that when she did say anything her gentle voice cut like a knife.

"You?" her husband asked, uncomprehending.

No one else spoke.

Alicia said, "There are times-times when I simply can't stand it any more-when I need some escape."

"Can't stand what?" he asked.

Reluctantly, sadly, but beyond tears now, she said, "This house, my family, the coldness, the way we seldom speak to one another, the fact that we barely know each other..."

Jubal was speechless. This was a time of changes, large changes, or at least a time of intimations of changes, and he was going to have to make a great many adjustments, examine a long list of his cherished att.i.tudes. None of it would be easy.

"Have you noticed that you're missing any TDX?" the cyberdetective asked the lonely woman.

"I haven't noticed."

"We'll look later," St. Cyr said. "But I'm certain that your supply has been reduced."

"Okay, okay," Jubal said, suddenly impatient, trying to wipe out his hurt and confusion with feigned anger. "The proof is conclusive. But who got to Teddy? Who re-programmed him with all these directives to kill?"

"May I try to answer that?" Hirschel asked. He was grinning, his hands swinging at his sides, like a high school kid meeting his first date.

"Go on," St. Cyr said.

"Teddy was never re re-programmed," Hirschel said.

"Right," the detective said.

"The illegal directives were worked into his program in the factory," Hirschel said. "From the moment that he came here, he was prepared to kill everyone in the house."

"Once he had made the proper impression, generated trust, and got the necessary tools together," St. Cyr added.

Hirschel smiled and said, "And the man who programmed him was Walter Dannery."

"The man I fired?" Jubal asked.

"The same," Hirschel said. "Right?"

"I believe so," St. Cyr said.

"But that's insane!" Jubal said.

"I have no certain proof of it yet," the cyberdetective said. "But I probably will have in the morning-at least a bit of circ.u.mstantial evidence. Consider that Reiss Master Units are produced on Ionus, the same world to which Dannery went after he lost his job here. Also consider that he was one of your chief roboticists, as you've told me, and would very likely be a candidate for executive-level employment with Reiss."

Jubal looked as if he had been caught on the back of the head by a boomerang just after stating flatly that such toys didn't work.

St. Cyr got down from the table and began to put the evidence into the paper sack again. He said, "Did you have any proof-anything admissible in a court of law-that it was Walter Dannery who embezzled those funds?"

"He was in charge of that section and the only human authorized to handle the books. And computer tapes had been altered, rather crudely in fact. We couldn't flatly prove that it was Dannery-but we knew that it couldn't be anyone else." He sounded defensive, without reason.

"Therefore," the detective said, twisting the top on the bag, "no charge was leveled against him with Darmanian authorities."

"None," Jubal said.

"And without a mark on his work record, Reiss would have no reason to pa.s.s up his application for a job."

Jubal still could not accept the devious resurrection of the past. He said, "But the man embezzled the money. He knows he did. Knowing he was guilty, wouldn't he be relieved at getting off so lightly? When he'd had time to think it over, would he feed his hatred until he was willing to commit murder?"

"People have killed for less," St. Cyr said. "And it may just be possible that he was not lying to you when he told you that sob story about dependent children and a sick wife. If you'll excuse my saying so, you are not a proper judge of human emotions, not sensitive enough to such things to distinguish between a lie and the truth."

Jubal apparently was willing to accept the judgment. He said nothing more, but he looked at Alicia and took her hands and held her beside him, close.

"Question?" Tina asked.

"Yes?"

"How could Walter Dannery have known the circ.u.mstances of daily life in this house? He would have had to be familiar with so much to have so minutely programmed Teddy. For instance, he would have to know about the wolf skins in storage, about Dane's superst.i.tions-"

"Not at all," St. Cyr interrupted. "All that Dannery needed to do was implant the prime directive: 'Kill everyone in the Alderban family, but protect yourself against discovery.' He would have needed a number of qualifying directives, of course: 'Choose an exotic means of murder; establish suspects outside of yourself; to all overt intents and purposes, perform according to the Three Laws of Robotics..." He may even have chosen the werewolf scheme, since he lived on Darma and may have known the legends. After that, however, it was up to Teddy to work out a viable plan for the extermination of the family. Remember that a master unit has a fantastic capacity for the storage of new data, while its logic circuits are four times as large and eight times better than those in the bio-computer that I wear. With the minimum of directives, Teddy could have worked out the rest of it."

"Now what do we do?" Alicia asked.

"We call Teddy in here and ask him to open his service panel for inspection. Unless I miss my guess, I believe he will obey. We simply shut him down."

"Like pulling a plug," Hirschel said.

St. Cyr crossed the room, opened the door and said, 'Teddy?"

Teddy did not respond.

St. Cyr stepped into the hall. "Teddy, come here, please."

He received no answer.

"Where is he?" Hirschel asked.

"Gone," the cyberdetective said. "I seem to have guessed wrong. Apparently he was eavesdropping through the house computer."

FOURTEEN: Confrontation with the Killer

Hirschel maintained a small a.r.s.enal in his suite on the fifth level-pistols, rifles, revolvers, traps, and more insidious devices-and it was here that they armed themselves before making a thorough search of the mansion. Conventional weapons, for the most part, were useless against a robot, because the projectiles from few rifles-and from no handgun known-could be expected to pierce quarter-inch multi-pressed steel. In Hirschel's collection, however, were four vibra-beam weapons, guns that projected a powerful but rapidly dissipating beam of sound, carried and magnified in a high-intensity laser that moved on a line-of-sight between hunter and target. The light was visible as a quick flash, the sound beyond the range of the human ear. In close quarters, the weapon could kill a man and pretty well mangle the innards of a robot. Two of Hirschel's pieces were rifles, which he and St. Cyr chose, since they were more familiar with weaponry and would know how to use a rifle within the confines of a room, if the opportunity should come for that Tina and Dane took the pistols.

"We'll stay together," St. Cyr said. "Dane and I will walk abreast, Jubal and Alicia behind us, Hirschel and Tina at the rear. Keep your eyes open; we won't hear him coming if he doesn't want us to."

In the corridor, St. Cyr picked up the nearest phone link to the house computer and directed it to turn on and keep on every light in the mansion. Teddy had night vision. They didn't. He further ordered the house to shut down all but one elevator, which only they would be permitted to use. Without curiosity, the computer obeyed.

"Can a master unit override the orders I just gave the house?" the detective asked Jubal.

"No." Tired. Confused. Rich, yes, but what did that matter now?

"Perhaps, if he tampered with it-"

Jubal shook his head fiercely. "The house computer is a perpetual care unit that repairs itself. It's housed in the rock strata under the mansion, sealed up tight. There is absolutely no way that Teddy could have gotten to it."

"Good enough," St. Cyr said. He was beginning to feel as if it was all so much ritual from this point on, the obligatory chase before the inevitable ending. "We'll leave the bag of evidence in Hirschel's room. It contains Teddy's gun and claw, his two major weapons. That makes him less dangerous but not harmless, so watch your back while we're checking out the rest of these rooms." In fifteen minutes the fifth level was cleared. St. Cyr lifted the phone link to the house computer and said, "I want you to lock all the doors, patio doors and windows on the fifth level, inside and out I don't want you to unlock them except when you're told to do so by a human voice."

"Yes, sir."

He hung up and turned back to the others, grimaced and picked up the phone again.

"Yes?" the house asked.