Truls snorted.
‘But God knows if he was guilty,’ Aune said. ‘That’s why I prefer the method they used in ancient India.’
The door opened, and Sethi and his bed were wheeled in by two nurses.
‘Listen, Jibran, you’ll like this too,’ Aune said.
Harry had to smile. Aune, the most popular lecturer at Police College, holding forth again.
‘The suspects were admitted one by one into a room that was pitch-dark, and told to feel their way in the darkness until they found a donkey which was standing in there and then to pull it by the tail. If they’d lied under questioning the donkey would shriek or bray or whatever it is donkeys do. Because this particular donkey was, the priest informed them, a holy donkey. What he didn’t tell them was that the tail was smeared with soot. So when the suspects came back out and said that, yes, they had pulled the donkey’s tail, all they needed to do was check their hands. If they were clean, it meant the person had been afraid the donkey would expose the fact he had lied, and he was sent to the gallows or whatever they used in India at the time.’
Aune glanced over at Sethi, who had taken out a book, but nodded ever so slightly.
‘And if he had soot on his hands,’ Øystein said, ‘then all it meant was the guy wasn’t a complete moron.’
Truls grunted and slapped his thighs.
‘The question,’ Aune said, ‘is whether Røed walked out of there with soot on his hands or not.’
‘Well,’ Harry said, ‘what we carried out was probably more of a cross between the old photocopier trick and the holy donkey. I’m pretty certain Røed believed this was a lie detector.’ He pointed at the table with Truls’s laptop and the leads and electrodes they had borrowed from down on the third floor, where they were used for ECG monitoring. ‘So, I do think he was wary of lying. But he passed the donkey test in my opinion. He showed up and took what he believed to be a real test. That in itself indicates he doesn’t have anything to hide.’
‘Or,’ Øystein said, ‘he knows how to fool a lie detector and wants to use that to mislead us.’
‘Mm. I don’t think Røed is trying to deceive us. He didn’t want Truls on the team. Understandably so, as the whole project would lose credibility if it became known. It was only when we convinced him about how much it meant to gain access to the police reports that he agreed. Yes, he wants some names to make his investigation appear serious on paper and in a press release, but finding out the truth is even more important to him.’
‘You think?’ Øystein said. ‘Then why refuse to give a DNA sample to the police?’
‘I don’t know,’ Harry said. ‘As long as there’s no reasonable suspicion, the police can’t force anyone to take a DNA test, and Krohn says volunteering a test is tantamount to an implicit agreement that there is reasonable suspicion. Anyway, Alexandra has promised me an answer within days.’
‘And you’re sure the profile won’t match the saliva found on Susanne?’ Aune asked.
‘I’m never sure of anything, Ståle, but I crossed Røed off my list of suspects when he knocked on the door of my hotel room today.’
‘So what do you want with the DNA analysis?’
‘To be sure. And have something we can give to the police.’
‘So they don’t arrest him?’ Truls asked.
‘So we have information to offer them, and they might give us something in return. Something not in the reports.’
Øystein smacked his lips loudly. ‘That’s, like, smart.’
‘So with Røed out of the running and a brain that’s been removed,’ Aune said, ‘do you still believe the killer is someone with a connection to the victims?’
Harry shook his head.
‘Good,’ Aune said, rubbing his hands. ‘Then maybe we can finally start looking at psychopaths, sadists, narcissists and sociopaths. In short, the more interesting portion of humanity.’
‘No,’ Harry said.
‘All right,’ Aune said, looking miffed. ‘You don’t think the perpetrator is to be found within their ranks?’
‘Yes, I do, but I don’t think we’ll find him there. We’re going to look where we are best equipped to find something.’
‘Which is somewhere we assume he isn’t?’
‘Exactly.’
The three men looked at Harry with incomprehension.
‘It’s pure mathematics,’ Harry said. ‘Serial killers pick their victims at random and cover their tracks. The probability of finding them in the space of a year is less than ten per cent, even for the FBI. For the four of us, with the resources we have? Let’s just put it at two per cent, to be kind. If, on the other hand, the killer is to be found among the victims’ acquaintances and there’s an understandable motive, the chances are seventy-five per cent. Let’s say there’s an eighty per cent probability the killer is in the category Ståle wants us to look at, let’s say it is a serial killer. If we focus on that category and exclude the victims’ acquaintances, then the chances of us succeeding are...’
‘One point six per cent,’ Øystein said. ‘And the probability of success if we concentrate on people the victim knew is fifteen per cent.’
The others turned in surprise to Øystein, who flashed them a broad, brown grin. ‘Have to have a head for numbers in my job, you know.’
‘Pardon me,’ Aune said. ‘I hear the numbers, but to be honest it feels slightly counter-intuitive.’ He registered the look Øystein gave him. ‘Contrary to common sense. To look where we don’t think they are, I mean.’
‘Welcome to police investigation,’ Harry said. ‘Try to think of it this way. If the four of us find the guilty party... fantastic, jackpot. If we don’t then we’ve done what detectives do on most of their working days, we’ve contributed to the total investigation by eliminating some people from our inquiries.’
‘I don’t believe you,’ Aune said. ‘What you’re saying is rational, but you aren’t so rational, Harry. You’re not the type to do work based on percentages. Yes, the professional side of you sees that all the circumstantial evidence points to a serial killer. So you’re of the opinion it’s a serial killer, but you believe something else. Because your gut tells you so. That’s why you’ve come up with this calculation, you want to convince yourself and us that the right thing to do is follow the gut instincts of Harry Hole. Am I right?’
Harry looked at Aune. Nodded.
‘My mother knew God didn’t exist,’ Øystein said. ‘But she was still a Christian. So who are we going to, like, eliminate as suspects?’
‘Helene Røed,’ Harry said. ‘And the guy selling coke at the party.’
‘Helene, I understand,’ Aune said, ‘but why the drug dealer?’
‘Because he’s one of the few people at the party who hasn’t been identified. And because he turned up in a face mask and sunglasses.’
‘So what? Maybe he hasn’t been vaccinated. Or suffers from mysophobia. Sorry, Øystein, a fear of bacteria.’
‘Maybe he was sick and didn’t want to infect people,’ Truls said. ‘But did all the same. The reports say both Susanne and Bertine had a high temperature a couple of days after the party and at any rate, felt unwell.’
‘But now we’re overlooking the most obvious reason,’ Aune said. ‘A drug dealer is, after all, involved in something which is highly illegal, so it’s hardly remarkable he should wear a mask.’
‘Øystein,’ Harry said. ‘Explain.’
‘OK. If you sell... let’s say cocaine, then you’re not that worried about being identified. The police know pretty much who is selling on the street anyway and they don’t care, it’s the men behind the scenes they want. And if the police bust you, it happens during the transaction, and then a mask isn’t gonna be much use to you. So it’s the other way round — if you’re going to sell on the street, then you want the customers to recognise your face and remember that you sold them good shit the last time. And if you offer home deliveries, which it sounds like this guy does, then it’s even more important that the customer sees and trusts your honest face.’