Skinner gazed out of the window of the office at a truck being backed out, its reversing alarm echoing inside the garage.

‘Has Brian got the baby with him? Luanne?’ he said.

‘We believe so, sir.’

‘Shit. I hope you find them.’

‘So do we.’ Fry paused. ‘Speaking of Luanne, we know about the adoption. Mr Mullen’s father-in-law has explained to us that Brian and Lindsay couldn’t have any more children, because Brian was infertile after a bout of mumps.’

‘Mumps?’ said Skinner. ‘Is that what he told you?’

‘Certainly. He said the illness caused physical damage that made Brian become infertile.’

‘Well, it’s not what Brian told me at the time. Mumps had nothing to do with it.’

‘So what was it, then?’

‘STD.’

‘A sexually transmitted disease?’

‘That’s right. I can’t remember the exact name, though. Something with “clam” in it.’

‘Do you mean chlamydia?’

‘Yes, that’s what Brian had. And it wasn’t the first time, either. Chlamydia was what caused the damage. He told me all about it. If you get it too often, it causes scarring and blocks the – you know, the passage.’

Fry stared at him, her mind adjusting to a series of new possibilities. ‘Not mumps?’

‘I wonder if mumps was what he told his in-laws,’ said Skinner. ‘I met Henry Lowther once. He’s the sort of bloke who likes everything to seem right and proper. Even his son-in-law – since he’s stuck with him.’

‘Does Brian not get on with the Lowthers?’

‘Well, you know what it’s like. He wasn’t really good enough for their daughter from the start. They’d have preferred Lindsay to marry someone loaded. A step up on the social scale, if you know what I mean. Not a few steps down, like Brian.’

‘Mr Skinner, were you aware of any problems in the Mullens’ marriage? Was there any trouble between Brian and Lindsay?’

‘Trouble? Why should there be?’

‘Well, for a start, I presume Lindsay knew about the chlamydia? That would make quite a difference to their relationship, I think.’

The idea seemed to strike Skinner for the first time. ‘You think she might have blamed Brian for the fact that they couldn’t have another child naturally? Lindsay really, really wanted a daughter, you know.’

‘Yes, I know that.’

Skinner nodded. ‘That would make her a bit upset with him, I suppose.’

‘Well, yes,’ said Fry. ‘And there are other things that might have upset her, too – like where her husband picked up an STD in the first place.’

‘Hey, you’re right. I imagine there were a few words exchanged.’

‘But Brian never mentioned anything like that to you?’

‘Do you know, there were times when he was a bit pissed off, and I reckoned he might have had problems at home. But he never explained why – we didn’t talk about things like that.’