Fitzduane smiled. They walked toward the path that ran along the bank of the river. Downstream, minutes away, was the KirchenfeldBridge, and just below that was the spot where Klaus Minder's body had been fished out.
The Bear sat down on a bench. Suddenly he looked tired. He threw a small branch into the water, and his eyes followed it until it bobbed out of sight. He extracted a creased envelope from his pocket and smoothed it on his knee.
'Your guess as to the Hangman's identity,' he said. 'I found it in my pocket when I was getting dressed in the hospital this morning.'
'It seems I was wrong,' said Fitzduane dryly. 'There doesn't seem to be much doubt that Lodge is our man, and God knows where he is now. Your people have checked every square millimeter of Bern over the last couple of weeks.'
'Why did you think it was Balac?'
Fitzduane picked up a handful of pebbles and slowly tossed them one by one into the river. He liked the faint plop each stone made. He wondered how many people had sat on the riverbank over the years and done the same thing. Had a vast bed of pebbles built up in the river as a result? Would the river eventually be choked up by ruminating the river watchers?
'A number of reasons. For starters, just sheer gut feeling that he is a person who is not what he seems. Next, a number of small things. He is the right age. He was an intimate of Erika's. He has the right kind of charming but dominant personality. His artist's training would give him an excellent knowledge of anatomy. His work habits allow him to travel extensively without suspicion, to have unexplained absences, and so on. He's paranoid about security. His studio is near where Klaus Minder's body was found. There are other pointers, but none conclusive, and in any case it all appears a little academic at this stage. We've identified our man, and he isn’t Balac.'
'Hmm,' mused the Bear. He was no longer looking so tired.
'Anyway, I can't see him doing something as provocative as the chessboard girl.'
'We're dealing with a player of games,' said the Bear. 'The Hangman isn't rational by normal standards. He has his own logic. Tweaking our collective official nose appeals to him. Actually it’s not so uncommon. I once picked up a car thief who had operated freely for years until he stole a police car – and to an unmarked one, but the full painted-up job with radio and flashing lights and all the trimmings. When I asked him why he'd done such a stupid thing, he said he couldn’t resist it.'
Fitzduane laughed. 'How are you feeling?'
'Good considering this is my first day out of the hospital, but I do get a little wobbly now and then. I'll take a good long rest when this is over.'
'I'm not sure you should go to this meeting.'
'You couldn’t keep me away if you tried,' said the Bear. 'Don't forget I've a very personal interest these days. I want the Hangman dead.'
'What about civil rights and due process of law?' said Fitzduane, smiling.
'The Bear shook his head. 'This isn't a normal case. Normal rules don't apply. This is like stamping out a plague. You destroy the source of the infection.'
They walked along the Aare to the Dalmazibrucke. By crossing it and cutting up Schwellenmattstrasse, they could have made it to Project K in ten minutes, but Fitzduane took another look at the Bear and called a Berp car by radio. The Bear didn't argue. He was silent, lost in thought.
The Chief surveyed the assembled Project K team; then his gaze fixed on the Bear.
'You shouldn’t be here, Heini, as you damn well know. If you collapse, don't' expect me to hold one end of the stretcher. You're too damn heavy.'
The Bear nodded. 'Understood, Chief. You're not a young man anymore.'
'Needs his strength for other things,' said Charlie von Beck.
'Shut up, the lot of you,' said the Chief, 'and listen carefully. A short time ago we had our first major breakthrough. We paid a heavy price, but we identified the Hangman's base in Bern, and we now have a fair idea who he is, though I admit there are some problems in that area. On the negative side, a couple of weeks after the Muri find, the investigation is virtually at a standstill. We are at an impasse in terms of the Hangman's identity, and the man himself seems to have vanished despite the fact that we now have a photograph of him – and dental records – to work with. To add insult to injury, the death of that dentist occurred after the Muri raid, so it looks very much as if the Hangman is still in Bern. We know what he looks like, yet this psychopath seems to come and go with impunity – and not just to look at the sights. He is still killing.
'I've called you all together to suggest that we change the way we're approaching this investigation. Since Muri we've been concentrating on trying to find Lodge to the virtual exclusion of all else. We haven't been successful. Now I think we need a more creative approach, and I include in that our use of the computer.' He nodded at Henssen.
Henssen stood up and then propped himself against a desktop. He looked as if he needed the support. He cleared his throat and spoke, his voice hoarse. 'The Chief thinks that we may have the solution in the computer but that we're not asking the right questions. He may well be right, so let me explain a little more about what we have done – and can do.
'Our identification of Lodge was the result of a mixture of computer activity and human judgment. We tapped into a vast amount of data and then constructed a theoretical profile of the Hangman, and then, using a technique known as forward chaining, we filtered through the data. We were lucky. One of our two prime suspects was our man.'
'May I interrupt here?' the Bear broke in. 'I thought it was agreed that the initial profile would look for someone who wasn't Swiss. If so, why did the machine cough up Beat von Graffenlaub? His age wasn't right either.'
Henssen looked a little uncomfortable. 'Well, Heini, I owe you something of an apology. I second-guessed you. The program allows parameters to be graded according to the confidence rating because there wasn't a shred of hard evidence to back it up; it was outweighed by other material. The same applied to the age factor. In neither case were we dealing with hard facts, only with guesses.'
'Fair enough,' said the Bear, 'but I would like to have been told that at the time.'
'The system is totally transparent to the user,' said Henssen. 'Any of the parameters can be looked at whenever you wish. After this I'll show you how it's done.'
'Can we get back to the original topic?' said the Chief testily.
'Certainly,' said Henssen. 'Where was I?'
'Forward chaining,' said Kersdorf.
'Ah,' said Henssen. 'Well, forward chaining is essentially a way of generating conclusions by applying rules, either formal or heuristic, to a given set of facts. If the bank customer pulls a gun and demands money and there is no suggestion that this is a security test, then a reasonable deduction is that he is a bank robber.'
'And who said computers couldn’t think?' Charlie von Beck rolled his eyes. He was back in his bow tie and velvet suit.
Henssen ignored the interruption. 'The point is, forward chaining is only one way to go about things. You can also use backward chaining. In that situation you could assume someone was a bank robber and then work back to see what facts supported that conclusion. It's an ideal way of checking out a suspect and ties in with the less rational elements of our human makeup, like intuition.'
The Bear caught Fitzduane's eye and smiled.
'What it comes down to,' the Chief said, 'is that we have a much more flexible tool here than we seem to realize, and we're not using it to anywhere near its full potential. For instance, it can function in the abstract. Instead of asking, ‘Who do we have on file who has a knowledge of plastique?’ you can ask it, ‘What kind of person would have a knowledge of plastique, and where might he or she be found?’ The machine will then generate a profile based upon its file of data and its knowledge base.' He rose to his feet. 'Well, there you have it. Take of the blinkers. Try a little creative anarchy. Hit the problem from first principles. Find the fucking Hangman.' After an angry look at everyone, he left the room.
