At first, Owen had joined innocent newsgroups on national parks and non-league football. He had found a website for the Dry Stone Walling Association. But then he had begun to notice spam messages on the newsgroups, and out of curiosity he had visited the sites they were promoting. He had been absolutely amazed at what he had found. Amazed and guiltily fascinated. There had never been anything like that in the house at Cargreave, certainly not when Mum was alive.

‘If a TV programme got a bit saucy, we had to switch it off,’ he said.

Then Owen learned how to download images on to his hard drive. He had found that he was spending more and more time on the net, surfing from site to site. He realized he was becoming addicted, but he couldn’t stop. He had missed parish council meetings for the first time, and people in Cargreave had thought he must be ill. He had been spending entire evenings on the internet, forgetting to eat, staying up into the early hours of the morning.

DCI Tailby nodded at that. The police team had found Owen’s latest phone bill – it showed three hundred hours of calls to an 0845 number.

Owen said he had given his address several times when asked to register for free access to new sites. Then he had suddenly found that he was in contact with other people around the world, people he had never heard of, who sent him e-mail messages. He was delighted that they addressed him as if he were an old friend. They seemed to regard him as someone with the same interests. He had become part of their community.

When Mark Roper had been sent home and Owen Fox had been allowed a break, Diane Fry found DI Hitchens already in the DCI’s office. They watched her warily when she produced a report sheet from the folder she carried.

‘Yes, Fry? What have you got there?’

‘This is the latest surveillance report on Ringham Edge Farm.’

‘Have we still got that surveillance on?’

‘We have. This is the report from last night.’

‘Riveting stuff, is it?’ said Hitchens.

‘Well, judge for yourself. On Friday, the two boys left for school at the usual time in the morning. Their father saw them off. After that, Warren Leach went about his normal work on the farm, as far as could be ascertained by the officers on surveillance duty. Their reports are a bit lacking in technical detail, but some of Leach’s observed activities did involve cows and a tractor, so I suppose we have to take it on trust.’

Tailby didn’t seem interested. ‘We could get Ben Cooper to de-brief them, I suppose. He might spot some anomalies, if you think it’s worthwhile.’