They went downstairs and through into the lounge, where the television was playing away to itself, a range of Saturday-morning chefs producing a selection of mouth-watering dishes.

‘And that’s not like Dad either,’ Janet Dawson said. ‘The telly being on.’

‘It was on when you arrived here this morning?’ Lucy asked.

‘Yes.’

‘Could he not just have left it on as a security measure while he was going out … you know, to make thieves think he was in?’

‘Yes, but he only does that at night.’

The implication was evident.

‘What time did you arrive this morning?’ Lucy asked.

‘Just after eight.’

‘So you’re worried the television might have been left on all night?’

The woman looked even paler than before. ‘I can hardly bear to think what that might mean if it’s true.’

‘Your father doesn’t own any other property that we might look around?’ Lucy asked. ‘An allotment with a shed perhaps? A garage?’

‘No, I’m sorry.’

‘Okay.’ Lucy walked back through the house to the kitchen, where she halted next to one of the spotless worktops. A mug containing a dry teabag and an unused spoon sat alongside the kettle. This was more suggestive than anything she had seen at the house so far.

Most telling of all, though, was the open back door.

Lucy pulled on a pair of disposable latex gloves.

‘Oh, my God,’ Janet Dawson moaned.

‘It’s just a precaution.’ Lucy checked along the door’s edge and down the edge of the door-jamb. ‘There’s no sign of any damage here.’

‘I don’t think anyone forced entry. I mean, there’s no damage anywhere. And it’s not like there’s any sign of a scuffle. Nothing’s broken, there’re no blood spots or anything.’

‘So, if someone came into the house this way,’ Lucy said, ‘your father must have let them in willingly.’

‘I suppose so.’ Janet Dawson gave a weak, forced smile. ‘That’s good, isn’t it?’

Lucy didn’t mention that most of the violence in modern society was inflicted by persons known to the victim. Instead, she said, ‘How many of your father’s house-callers are in the habit of coming to the back door?’

‘I must admit … I can’t think of any who would do that, or why.’

They crossed the garden together. It was smoothly turfed aside from a crazy-paved path, with a brick platform on the right covered in potted plants. At odds with all this neatness, the back gate hung ajar.

‘The gate was like this, this morning?’ Lucy asked, again noting an absence of damage, which meant that this hadn’t been forced open either.

‘Exactly like it is now.’

‘We shouldn’t necessarily read something bad into this,’ Lucy said. ‘There are lots of possibilities here at present.’