“What, Donald?”

“As you said, sir, this is a rather well-planned conspiracy. If, as you speculate, the assassins are planning to seize power, then they might well have co-opted the succession in advance. ”

Kresh nodded and thought for a second. A strange expression came over his face. “Unless we’re looking at this backwards. Maybe it’s some band of civic-minded madmen who did this.”

“What?” Justen asked.

Kresh gestured toward the bed. “He told me himself, last night, that he was close to being impeached or recalled. He was fairly optimistic about his chances of staying in office, but maybe someone else wasn’t.”

“So?”

“So the Governor’s choice as successor doesn’t get the job if he’s removed from office by impeachment or recall. If the Governor is booted out, the President of the Legislative Council takes over. Shelabas Quellam. Maybe someone didn’t want Quellam in the Governor’s chair. ”

“Is Quellam that bad?” Justen asked. “I hardly know the first thing about him. ”

“That’s about all there is to know,” Kresh said. “He’s as close to a nonentity as you would ever wish to meet. The trouble is that Grieg named Quellam as his Designate. Supposedly he felt the same man should take over regardless of the circumstances, for the sake of stability.”

“Are you sure of that?”

“Reasonably so,” Kresh said. “We’ll find out soon enough. Right now, I’m more interested in who killed the man, not who takes over from-”

But Kresh was interrupted by a woman who came in at the door. Justen recognized her as Fredda Leving, the roboticist. What the devil was she doing here? “Sheriff Kresh,” she said, “I’ve found something. ” There was an excited glint in her eyes, an edgy sort of triumph. “Follow me,” she said. She turned and left the two men standing there, not bothering to look behind to see if they were following.

“Ah, Dr. Leving is here at my request,” Kresh said, answering Justen’s question before he had a chance to ask it. “I wanted to pull in a robotics expert as soon as I could. ”

It took Justen a moment, but then he understood. “The SPRs,” he said. “How the hell did the shooter get past them?”

“That was my question,” Kresh said. “Let’s go see what she’s found.”

“There’s not much that I can see,” said Alvar Kresh as he peered into the recesses of the Sapper robot.

“That’s because you’re not in the business of dealing with these things up in Hades,” Fredda said. “But you will be.”

“Well, that sounds very dramatic,” Kresh said, “but all I can see is what looks like some sort of broken-off attachment clip and a torn bit of flat cable.”

“Let me have a look,” Devray said. Kresh stepped back and let the younger man peer into the robot’s interior. “It mean anything to you?” he asked.

Devray pulled his head out, a lot of astonishment on his face. “Burning devils. A restrictor.”

“What?” Kresh said.

“A restrictor. A broken-off connection point for a restrictor. Someone took the restrictors off a batch of New Law robots, modified them somehow to react to a different control system, and plugged them into these SPRs.”

Kresh opened his mouth to speak, but no words came out. The SPRs shut down by restrictors removed from New Law robots? That was diabolical.

Every New Law robot had a restrictor built into it. In principle, at least, the idea was simple enough. The restrictors saw to it that any New Law robot attempting to leave Purgatory would be shut down as it tried to go. It was supposed to be impossible to remove the device without destroying the robot. No restrictor-wearing robot could function outside the area permitted by the restrictor-which was to say, the island of Purgatory. The precise workings of the system were a closely held secret. Even Kresh did not know exactly how it was supposed to work.

But he did know the operative word was “supposed,” for the obvious fact was that the system did not work. Every rustback robot that left the island was a testament to that. That there was a traffic in them, a regular business, and that made it plain that it was not a question of occasional lapses or isolated violations. Rustbacking was more than just a business-it was a whole criminal industry, a highly sophisticated operation.

And one that was now tied into the assassination of the Governor. A gang of rustbackers hand found a way to tamper with the Governor’s own security robots. How the hell could they trace that leak?

“You’re sure that’s a piece off a New Law robot’s restrictor?” Kresh demanded.

“Absolutely,” said Fredda Leving. “It was what I was looking for when I started checking the Sapper robots.”

“But I don’t understand. We’re still on the island. Why should restrictors turn off the security robots?”

“They must have been modified in some way, “ Fredda said. “Clearly they weren’t working on a geographic basis, because the Sappers were working fine during the party. My guess is that they were modified to deactivate the robots on some sort of signal. Hyperwave, or maybe even old-fashioned radio. No one uses radio anymore-but that fact right there would make it perfect for this sort of job. The signal would be undetectable with any sort of modern equipment. Clearly the restrictors have been modified not only to shut down the robots in some different way, but also to be removable in a hurry. Except this restrictor didn’t come out quite as easily as it was supposed to.”

“But where the devil did they get the restrictors to put on the SPRs?” asked Devray.

There were times it was more than clear to Kresh that Devray did not think in terms of crime and victim and criminal. He was better suited to forest management than murder investigation.

“The spare parts bin,” Leving said. “Obviously, they used restrictors they had peeled off New Law robots. Rustbackers did this. No one else could have.”

“Well, one thing is for sure,” Kresh said. “Whoever did this worked in a rustbacker lab at some point. He or she knew how to get these things out, and do it in a hurry.”

“A rustbacker,” Fredda said. “Maybe that can point us toward a motive for the murder.”

“Maybe,” Alvar said. “At least now we can get started.”

Donald 111 was in a very slight state of shock, and it was with a great sense of relief that he found that his duties required him to be alone.

The SPRs had been tampered with. They had been shut down, useless for security work. Kresh had comforted him with the knowledge that Grieg had died with fifty robots to protect him. One more could have done no good. But the fifty had been useless, meaningless. One functioning robot could easily have made the difference. Worse, it was the deployment of the SPRs that had doomed Grieg-and Donald had urged their deployment.

Robots on the planet Inferno had always been built with extremely high First Law, and had been known to freeze up on occasions such as this, when they learned they could have prevented harm to a human. But Donald knew better than that. Yes, he could have saved Governor Grieg-if he had been possessed of information known to no one but those who killed the Governor. He could have saved him-if he had been here, at the Residence, instead of many kilometers away, with Kresh, performing his normal duties. He could have saved the Governor if a half-dozen impossible things had happened.

No. No. There was nothing he could have done outside the world of if-only. Here, in reality, it was never possible to avoid all risk, all danger. It was never possible to defend against attackers with as many resources, with as much willingness to take risks, as the killers of Governor Grieg.

But still, he needed to calm himself, to talk himself down from the idea that he could have done anything. So it was just as well he had work to do, and the need to do it in private.

There was a great deal more to a major investigation than discovering clues. It was, in many ways, as much a management operation as anything else, as Donald 111 had reason to know. There were all the logistical questions of bringing in robots and human personnel and all sorts of equipment. There was an evidence center to set up, where all the data could be stored safely, and the physical evidence protected from tampering and made available for examination. There was a press center to establish, accommodations for the investigation team and the press and the hangers-on and the VIPs who would inevitably arrive.