‘No worries. You look as though you could use it.’

At the sound of voices and footsteps, they both turned towards the door. But the voices went further away, down the corridor somewhere. After a minute or two, footsteps returned and the DI’s door closed again.

‘I think they’ve gone,’ said Murfin.

Cooper nodded. ‘But Diane is still in there.’

‘Looks like it. I suppose we’ll find out what’s going on eventually.’ Then Murfin sighed deeply. ‘Or maybe not.’

The squeak of the chair in the DI’s office was really starting to get on Fry’s nerves now. Yet the noise seemed to give Hitchens some perverse pleasure, especially as he’d physically prevented a maintenance man from oiling the thing when she’d suggested it.

‘So do you have any evidence that Luanne Mullen is in imminent danger, Diane?’ he asked when she put her proposal to him after the departure of the Lowthers.

‘Well, no.’

‘Has she ever been mistreated by her father? Has he ever threatened to harm her?’

‘Not that we know of.’

‘What about Brian Mullen himself? A few days ago, you were convinced he was responsible for the fire that killed his family. Have you managed to substantiate a case against him?’

‘No.’

‘So we’ve no cause to arrest him, have we?’

‘No.’

‘And we don’t actually have the slightest bit of proof that he’s done anything wrong.’

‘No. But we should also consider Georgi Kotsev’s theory that Luanne Mullen’s natural father is trying to get her back’

‘Yes, we’d have to take that seriously, if there was evidence,’ said Hitchens. ‘Is there evidence, Diane?’

‘I can’t produce any right now.’

‘You see the problem. No evidence. It’s all supposition.’

‘That might be true, sir. But the fact that Brian Mullen has gone AWOL with the surviving child looks very suspicious to me.’

‘Sadly, he’s not legally obliged to keep us informed of his whereabouts. If he’s taken the child for a trip somewhere, then there’s nothing we can do about it. Nothing at all.’

‘But the Lowthers are being equally secretive. I’m sure they know where Brian is.’

‘Have you asked them?’

‘Of course.’

‘And what do they say?’

‘They say their son-in-law is distressed and needs some time away from being hassled by us.’

Hitchens smiled. ‘I suppose that could be true, too, couldn’t it?’

Fry wasn’t amused. ‘I assure you, sir, I don’t hassle members of the public.’

‘Of course not, Diane. You’re a model of respect and discretion.’

She felt her jaw tighten, and tried to relax her muscles in case she looked too tense or aggressive.