Hitchens kept his chair still for once, instead of making it squeal on its swivel. Perhaps he was finally reading her thoughts, responding to the force of her unspoken will. Fry made a mental note to ask someone to come in and oil the thing when the DI was off duty.

‘The SOCOs found Wade’s digital camera,’ he said. ‘But all the photographs of the fire had been deleted from the memory card.’

‘I’m not surprised,’ said Fry. ‘He was worried we might find something incriminating.’

‘Like what?’

‘I think he probably started taking photographs long before he made the 999 call. We’d have been able to see the time of each photograph on the memory card, wouldn’t we?’

‘Yes, that’s right. Or even on a jpeg copy if he’d emailed them.’

‘Well, then it might have occurred to us to compare them to the time of his call. And he’d have some difficult questions to answer. I don’t think our Mr Wade is too technical. He wouldn’t have known how to check the time stamp of each photo, so he deleted the whole lot.’

‘You must have had him worried from the start, Diane.’

‘He was an amateur. Look at how many mistakes he made.’

‘Well, you always said the answer to the Mullen case would be close to home.’

‘I didn’t mean it like that,’ said Fry. ‘I was thinking about a member of the family. But I suppose your next-door neighbour is pretty close. The Mullens put their trust in him.’

Hitchens stood up from his chair. ‘Let’s go and see the DCI.’

In the DCI’s office, they found that Kessen had just received the results of the latest actions from the incident room – a detailed assessment of Rose Shepherd’s financial circumstances.

‘Miss Shepherd had several savings accounts at different banks,’ he said, ‘but they were practically empty. Unless there are some investments or deposits we haven’t located, the victim’s funds were getting dangerously low.’

‘She doesn’t seem to have had any income, either,’ pointed out Fry.

‘That’s right. Apart from interest on her savings, nothing has been added to any of the accounts as far back as we can go. Since the house purchase, the flow of money has been in one direction – into her current account, where it’s been used to pay bills. We had a quick calculation of her annual expenditure. At her present rate, she couldn’t have survived more than another six months, I reckon.’

Fry took the print-out he offered her. ‘Was she spending heavily?’