“I’m saying that Tierlaw ordered the Sapper, the SPR sentry robot, to be out of position. But a Sapper won’t take orders from just anyone. He-or a subordinate, more likely-must have gotten to the robot sometime before and used some rather sophisticated order giving to convince the sentry that orders from him, from Tierlaw, took precedence over everything else, even guarding Grieg. ”
“Is that possible?” Devray asked.
“Yes,” Fredda said. “If the SPR did not believe Grieg was in any particular danger, so that First Law potential was reduced, and if it saw Tierlaw as its owner, thus enhancing Second Law potential, then yes, Tierlaw could have given the order for the sentry to clear off and come back later. ”
“It’s thin,” Cinta said. “And I don’t see what it has to do with anything. ”
“It is thin,” Kresh admitted. “I knew that as soon as I figured it out. I knew I needed proof-and I found it. But there is more. Caliban and Prospero were witnesses that Tierlaw came out the inner door to Grieg’s office. After-hours visitors to his office always used the outer side door. But Tierlaw needed to let Bissal in. So he got Grieg to open the inner door somehow.”
“But he did not let Bissal in. He let us in,” Caliban said.
“And why would he let Bissal see his face?” Cinta demanded.
“He wouldn’t let Bissal see him,” Kresh said, heading over to his desk. “He didn’t. ” He unsealed the evidence box and pulled out a pocket communicator, and a thin piece of black metal in the shape of a flattened triangle. “I found these in your room, Verick, the one you stayed in the night of the murder. You’re good at hiding things. The room had been searched twice before I went over it. But I knew what I was looking for-and that makes a great deal of difference. And before you can protest that these were planted, a Crime Scene Observer robot witnessed the search and recorded it.”
“I recognize the communicator, but what’s the other thing?” Fredda asked.
“It’s one of these,” Kresh said. He went to the inner door of the office and used the scanner panel to open it. Once it was open, he took the piece of metal and set it in the frame of the door. It stayed there of its own accord. Kresh stepped back, and the door closed-but not all the way. There was a barely discernible crack between the frame and the sliding door. Kresh got his fingers into the crack and pulled. It took a bit of effort, but he managed to get the door open. Kresh took the door wedge out of the frame, crossed the room, and put it back in the evidence box.
“Grieg was supposed to be killed right here,” he said. “In this office. Verick would set the door wedge on his way out-with a little practice, they’re easy to set surreptitiously. Tierlaw would order the office door sentry robot back into position, and then signal Bissal, waiting in the basement, to turn on the range restrictor signal that would deactivate the SPR robots. Then Tierlaw could simply walk out of the house, unobserved, while Bissal came up out of the basement, came into the office, and shot Grieg. Bissal would remove the door wedge, and go on with the rest of the plot-destroying the robots to hide the restrictors, and then escaping to the warehouse, where he would hide until things cooled off-except the food left for him there was poisoned. He must have died within a few hours of Grieg.”
“That’s the craziest plan I’ve ever heard,” Cinta protested. “It could never work.”
“And it didn’t, “ Devray said. “It was crazy, Cinta, but think what we would have found if it had worked. Grieg dead behind a locked door, fifty wrecked security robots, and an assassin who simply vanishes without a trace. A few days later, a warehouse blows up and bums down, and no one ever thinks to connect the two. Things are bad enough as they are. People are scared. Just imagine the panic, the chaos, if the murder had been as smooth, as perfect as it was supposed to be.”
“But things went wrong,” Kresh said. “Things went wrong. The two robots are waiting outside the door, so you can’t set the door wedge, could you, Verick? And you couldn’t use your communicator in front of the robots, either. So you slip into a vacant room and contact Bissal from there, telling him what had gone wrong. You tell him to go to plan B, killing Grieg in his room.
“But then you realize that you couldn’t leave the vacant room. At a guess, one of the sentries on random patrol takes up a post in the hall. If you leave the room, that would raise the alarm. So you had to stay there, in that room, until the robots left, until you heard Grieg go to bed. You could signal Bissal. Then Bissal activates the range restrictor signal, and the sentries go dead. But even then you can’t leave, because Bissal has come up into the house. Suppose he saw you, and knew who you were? He’d have a hold over you. Suppose he tried to blackmail you instead of going off to eat his poison at the warehouse? No, you could not risk that. So you decide to wait until you heard Bissal leave the house.
