Silence.
Harry coughed. ‘OK, Bjørn, out with it.’
‘Out with what?’
‘What you’ve been brooding about ever since we got here.’
The forensics officer scratched his sideburns while eyeballing Harry. Coughed once. Twice. Glanced at Kaja as if to solicit help there. Opened his mouth, closed it.
‘Fine,’ Harry said. ‘Let’s move on to—’
‘The rope.’
The other two stared at Bjørn.
‘I found shells on it.’
‘Oh yes?’ Harry said.
‘But no salt.’
They were still staring at him.
‘That’s pretty unusual,’ Bjørn went on. ‘Shells. In fresh water.’
‘So?’
‘So I checked it out with a freshwater biologist. This particular mollusc is called a Jutland mussel, it’s the smallest of the pool mussels and has been observed in only two lakes in Norway.’
‘And the nominations are?’
‘Øyeren and Lyseren.’
‘Østfold,’ Kaja said. ‘Neighbouring lakes. Big ones.’
‘In a densely populated region,’ Harry said.
‘Sorry,’ Holm said.
‘Mm. Any marks on the rope that tell us where it might have been bought?’
‘No, that’s the point,’ Holm said. ‘There are no marks. And it doesn’t look like any rope I’ve seen before. The fibre is one hundred per cent organic, there’s no nylon or any other synthetic materials.’
‘Hemp,’ Harry said.
‘What?’ Holm said.
‘Hemp. Rope and hash are made from the same material. If you fancy a joint, you can just stroll down to the harbour and light up the mooring ropes of the Danish ferry.’
‘It’s not hemp,’ Bjørn Holm said over Kaja’s laughter. ‘The fibre’s made from the elm and the linden tree. Mostly elm.’
‘Home-made Norwegian rope,’ Kaja said. ‘They used to make rope on farms long ago.’
‘On farms?’ Harry queried.
Kaja nodded. ‘As a rule every village had at least one rope-maker. You just soaked the wood in water for a month, peeled off the outer bark and used the bast inside. Twined it into rope.’
Harry and Bjørn swivelled round to face Kaja.
‘What’s the matter?’ she asked hesitantly.
‘Well,’ Harry said, ‘is this general knowledge everyone ought to possess?’
‘Oh, I see,’ Kaja said. ‘My grandfather made rope.’
‘Aha. And for rope-making you need elm and linden?’
‘In principle you can use bast fibres from any kind of tree.’
‘And the composition?’
Kaja shrugged. ‘I’m no expert, but I think it’s unusual to use bast from several different trees for the same rope. I remember that Even, my big brother, said that Grandad used only linden because it absorbs very little water. So he didn’t need to tar his.’
‘Mm. What do you think, Bjørn?’
‘If the compositon is unusual, it will be easier to trace where it was made, of course.’
Harry stood up and began to pace back and forth. There was a heavy sigh every time his rubber soles relinquished the lino. ‘Then we can assume production was limited and sales were local. Do you think that sounds reasonable, Kaja?’
‘Guess so, yes.’
‘And we can also assume that the centres of production and consumption were in close proximity. These home-made ropes would hardly have travelled far.’
‘Still sounds reasonable, but . . .’
‘So let’s take that as our starting point. You two begin mapping out local rope-makers near lakes Øyeren and Lyseren.’
‘But no one makes ropes like that any more,’ Kaja protested.
‘Do the best you can,’ Harry said, looked at his watch, grabbed his coat from the back of the chair and walked to the door. ‘Find out where the rope was made. I presume Bellman knows nothing about these Jutland mussels. That right, Bjørn?’
Bjørn Holm forced a smile by way of answer.
‘Is it OK if I follow up the theory of a sexually motivated murder?’ Kaja asked. ‘I can talk to someone I know at Sexual Offences.’
‘Negative,’ Harry said. ‘The general order to keep your trap shut about what we’re doing applies in particular to our dear colleagues at Police HQ. There seems to be some seepage between HQ and Kripos, so the only person we speak to is Gunnar Hagen.’
Kaja had opened her mouth, but a glance from Bjørn was enough to make her close it again.
‘But what you can do’, Harry said, ‘is get hold of a volcano expert. And send him the test results of the small stones.’