Cooper picked up the transparent evidence bag. He held it up to the light and turned it slowly. He could see that the tag pointed out by Petty carried a six-figure code number on one side, and identified itself, or the plastic grasshopper it was attached to, as ‘The Travel Bug’.

‘What does it say on the other side?’ said Fry.

Cooper spun the bag. ‘It says: “I go from place to place, picking up stories along the way.”’

Fry shook her head in frustration. ‘What about the notebook that was in the box with all this stuff?’

‘It’s just an ordinary spiral notebook,’ said Petty. ‘You can buy this kind of thing anywhere. As far as we can tell, it seems to be some kind of log book. The first page is headed “Petrus Two”, and various individuals have made entries at different dates.’

‘Such as?’

‘Such as “Itinerant Maggie”. She says: “Great location – another spot I’d never have visited, if it weren’t for the cache – many thanks.”’

‘It means nothing to me.’

‘Nor me.’

‘Sounds like some kind of treasure hunt, doesn’t it?’ said Cooper.

‘Does it?’ asked Fry. ‘A treasure hunt?’ She looked at the bagged items taken from the box. ‘That is not treasure, Ben. Not by anybody’s standards. It looks like the debris from the back of somebody’s kitchen drawer.’

‘I meant treasure in the loosest sense, Diane. The fun of a treasure hunt isn’t the value of what you might find, but the excitement of the hunt. It’s a quest. People are always figuring out ways to take part in quests.’

‘Really?’ said Fry.

‘If it helps,’ said Petty, ‘there’s a website address on the Travel Bug tag.’

There were shrugs all round the table. Fry looked across at Cooper.

‘Ben, you’re getting to be a bit of a whizz on the internet, aren’t you? See if you can find out what this is all about.’ She picked up the skeleton key-ring and spun it thoughtfully in its bag. ‘We need to know who’s been messing around up at that rock, when they were there, and why. If the people involved have no connection with our enquiry, then we need to eliminate them.’

‘OK.’

Fry put the key-ring back on top of the Beatrix Potter book, covering a quaint illustration of a fox wearing a coat and scarf. ‘Anyway, we’ve got some more news this afternoon. The forensic anthropologist had a toxicological analysis conducted on a sample from the first set of bones.’

Cooper looked at her. ‘Bones?’ he said. ‘You mean Audrey Steele’s remains?’

‘Yes, Ben. The old bones the walkers found.’