“Plug-in speech program,” Shelly said. “Right off the shelf. Verbalizes and parses from the natural language section of the CYC system. These speech programs always seem more intelligent than they are because their grammar and intonation are so precise. But they don’t really know that much about what the words mean.” She turned back to Ben. “Keep querying it, Ben, see if it has come up with any answers. You can use ordinary language because it has a large lexicon of criminal justice idioms.”
“Right. Tell me, Dick Tracy, what leads are you exploring?”
“I have reduced the search to three possibilities. One, that the stolen material was hidden nearby for later retrieval. Two, that is was removed by surface transportation. Three, that it was removed by air.”
“Results?”
“Hidden nearby, very unlikely. Surface transportation more probable. However removal by air is the most likely when all factors are considered.”
Benicoff shook his head and turned to Shelly. “What does it mean by most likely? Surely a computer can do better than that, give us a percentage or something.”
“Why don’t you ask it?”
“I will. Dick Tracy — be more precise. What is the probability of removal by air?”
“I prefer not to assign an unconditional probability to a situation with so many contingencies. For this kind of situation it is more appropriate to estimate by using fuzzy distributions rather than deceptively precise-seeming numbers. But plausibility summaries on a scale of one to one hundred can be provided if you insist.”
“I insist.”
“Hidden nearby — three. Removed by surface transportation — twenty-one. Removed by air — seventy-six.”
Ben’s jaw dropped. “But — suspend program.” He turned to the others, who were as astonished as he was. “We’ve investigated the air theory very thoroughly and there is just no way they could have flown the stuff out of here.”
“That’s not what Dick Tracy says.”
“Then it must know something that we don’t know.” He turned back to the computer. “Resume operation. What is basis for estimate of removed-by-air estimate?”
The computer was silent for a moment. Then, “No summary of basis is available. Conclusion based on weighted sum of twelve thousand intermediate units in discovery program’s connectionist evaluation subsystem.”
“That’s a common deficiency of this type of program,” Shelly explained. “It’s almost impossible to find how it reaches its conclusions — because it adds up millions of small correlations between fragments of data. It’s almost impossible to relate that to anything we might call reasoning.’’
“It doesn’t matter — because the answer is wrong.” Benicoff was irritated. “Remember — I was in charge of the investigation. The airport here at the plant is completely automated. Most of the traffic is copters, though we get executive jets as well as cargo VTOLs and STOLs.”
“How does an automatic airport work?” Brian asked. “Is it safe?”
“Safer than human control, I can assure you. It was finally realized back in the 1980s that more accidents were being caused by human error than were being prevented by human intervention. All aircraft must file flight plans before takeoff. The data goes right into the computer network so every airport knows just what traffic is going out or coming in — or even passing close by. When an aircraft is within radar range a signal identifies them by transponder and they are given clearance or instructions. Here at Megalobe all of the aircraft movements are of course monitored and recorded by security.”
“But security was compromised for that vital hour.”
“Doesn’t matter — everything was also recorded at the Borrego airport control tower, as well as the regional FAA radar station. All three sets of records agree and the technical investigation proved that it would have been impossible to alter all of them. What we saw were true records of all aircraft movements that night.”
“Were there any flights in or out of the airport during that hour?”
“Not one. The last flight was at least an hour before the blank period, a copter to La Jolla.”
“How big an area does the radar cover?” Brian asked.
“A lot. It’s a standard tower unit with a range of about one hundred and fifty miles. From Borrego it reaches out right to the Salton Sea to the east and across it to the hills beyond. Forty, fifty miles at least. Not as far in the other directions with all the hills and mountains that surround this valley.”
“Dick Tracy, activate,” Shelly said. “During the day in question, twenty-four hours, how many flights were recorded by the Megalobe radar?”
“Megalobe flights, eighteen. Borrego Springs Airport, twenty-seven. Passing flights, one hundred and thirty-one.”
“Borrego Springs is just eight miles away,” Shelly said, “but they had no flights in or out during the period in question, none that night at all. All three sets of radar records were identical, except for inconsequential minor differences, on all the passing flights. These are flights that are detected at the radar fringes that don’t originate or end in the valley.”
“There seems to be a lot of air traffic out here in the desert,” Brian said. “One hundred and seventy-six in one day. Why?”
“Business flights to Megalobe we know about,” Ben said. “Borrego Springs has a few commercial flights, the rest are private planes. The passing stuff is the same, plus some military. So we are back to zero again. Dick Tracy says that the stuff left by air. Yet there were no flights out of the valley. So how could it have got out of the valley? Answer that and you have the answer to the whole thing.”
Ben had phrased the question clearly. How could it have got out of the valley? There was a paradox here; it had to go out by air, nothing went out by air. Brian heard the question.
His implanted CPU heard the question as well.
“Out of the valley by truck. Out of the area by air,” Brian said.
“What do you mean?” Shelly asked.
“I don’t know,” he admitted. “I didn’t say that, the CPU did.” He tried not to smile at their blank expressions. “Look, we’ll go into that some other time. Right now let’s analyze this. How far could the truck have gone?”
“We worked out a computer model early in the investigation,” Ben said. “The maximum number of men to have loaded the truck, without getting in each other’s way, is eight. The variables are driving time from the gate to the lab, loading time, back to the gate. Once out of the gate the best figure we could come up with was twenty-five miles distance at fifty-five miles an hour. There were roadblocks up on every road out of here as soon as the crime was reported, well outside that twenty-mile zone. Radar covered the area as well, from copters and ground units, and after dawn the visual searches began. The truck could not have escaped.”
“But it did,” Shelly said. “Is there any way a truck and cargo could have been airlifted out? We don’t know — but we are sure going to find out. Let me at the computer, Ben. I am going to have this program check every flight recorded that day within a hundred- then a two-hundred-mile radius.”
“Couldn’t the criminals have gotten records of that flight erased? So there would be no traces at the time of the crime?”
“No way. All the radar signals are maintained for a year in FAA archives, as well as screen-dumps from each air traffic controller’s terminal. A good computer hacker can do many wonderful things, but the air traffic system is simply too complex and redundant. There are hundreds, maybe thousands, of different kinds of records of every detected flight.”
Shelly did not look up, was hard at work, oblivious of them as they left.
“Shelly doesn’t know about the implant CPU,” Ben said. “Was that what you were talking about?”
“Yes. I haven’t had a chance to tell you, but Dr. Snaresbrook and I have had some success in my accessing the CPU by thought alone.”