Fry nodded at the liaison officer, who came forward and put an arm round Mullen’s shoulders.
‘I tested the smoke alarm every month,’ said Mullen, with some difficulty.
‘By pressing the button?’
‘Yes.’
‘Did you realize that it only tests the sound of the alarm, not whether the detector itself is functioning?’
Mullen looked paler than ever. ‘No, I didn’t know that.’
Fry watched him for a few moments, but felt no nearer to getting inside his mind.
‘I’ll give you a lift to Darley Dale,’ she said. ‘That’s where you want to go, isn’t it?’
‘Yes, to my parents-in-law.’
When she’d got him in the car, Fry let him sit quietly for a while as they drove across Edendale. Many people would feel uncomfortable with the silence and want to make conversation. But not Brian Mullen. She left him to stew until they were out of town and heading towards the A6.
‘Tell me about the arguments you’d been having with your wife,’ she said.
‘What arguments?’ said Mullen.
‘According to your neighbours, there had been several rows between the two of you in recent weeks.’
He shook his head. ‘We had a row about the new carpet, that’s all. I didn’t think it was the most practical thing with three kids in the house. And I didn’t like the idea of Henry buying things for us all the time, either. I told Lindsay I could support my own family without his help.’
‘Yes?’
‘But she got her own way in the end. She could never say no to Daddy when he wanted to give her something. So it wasn’t much of an argument.’ Mullen twisted in his seat to look at her. ‘Is that what you meant?’
‘And the rest.’
‘No, no. We never had rows, as a rule.’
‘That’s not what I heard.’
‘Well, you’ve got it wrong.’
They entered Bakewell, and Fry had to concentrate as she negotiated the narrow streets and the busy roundabout in the middle of town. She was able to relax again as they approached the entrance to Haddon Hall. But there were only a few miles left now.
‘You told me earlier that Lindsay and her brother were very close,’ she said. ‘That can be a difficult relationship for a husband to deal with sometimes. How do you get on with John Lowther?’
‘Fine. Just fine.’
‘Not even a hint of jealousy, perhaps? If John bought presents for your children, it would be natural for a bit of resentment to creep in.’
‘Any resentment wasn’t on my side,’ said Mullen.
‘Ah. So you think your brother-in-law begrudged someone coming between him and the sister he was so close to? I can see how that might cause friction in the household. Did your arguments concern John?’
‘You’ve still got it wrong. And whoever told you that has got it wrong, too.’
And that was the last thing she got out of him. Mullen remained silent and sullen all the way to Darley Dale. Now and then, he glanced anxiously out of the window at people passing on the pavement, and once he gave a sudden start when a car pulled alongside them at the traffic lights. Fry had no idea what he was so worried about, but she didn’t think it could be her driving.
Finally, she dropped him off outside the Lowthers’ gate, and he thanked her ungraciously. Fry watched as Moira Lowther came out of the bungalow and hugged Brian near the chiminea. That was just like Mrs Lowther. Very keen on hugging people.
Instead of heading straight back to West Street, Fry decided to call at the mortuary to collect the pathologist’s report. Mrs van Doon was in her office and greeted her visitor personally.
‘Yes, all three of your victims had carboxyhaemoglobin levels over fifty per cent — which is sufficient in itself to account for death. Levels of up to ten per cent would be normal, anything more indicates inhalation of carbon monoxide. I believe there might also have been hydrogen cyanide present in the fumes from the fire. That’s a particularly potent toxin, with a rapid action.’
‘Where would that come from?’ asked Fry.
‘Hydrogen cyanide? It’s produced by materials which contain nitrogen — wool, silk. And polyurethane.’
‘Polyurethane, as in furniture foam?’
‘Yes, possibly.’
‘Which of those would explain why three people failed to escape from a house fire when they were woken by the smoke?’
‘Hypoxia resulting from high carbon monoxide levels. At the levels present in these individuals, I’d say they would certainly have been feeling ill and disorientated at the least. They might even have been unconscious.’
‘But we’re sure they died as a result of the fire?’
‘Yes. Soot particles can stain the mouth and pharynx of a person who’s already dead, but if soot is present beyond the vocal cords it means the victim was alive during the fire.’
The pathologist produced a photograph. It was meaningless to Fry, which was probably for the best.
‘All three post-mortems showed evidence of soot in the airways. The two children also had it in the oesophagus and stomach. Those black streaks on the mucus of the trachea indicate that your victims were alive at the start of the fire. Alive, but not necessarily conscious.’
The waitress from the Riber Tea Rooms had arrived at West Street to be guided through the process of producing some e-fit pictures of the people Rose Shepherd had met in Matlock Bath the day before she died. She did her best, but she wasn’t sure about the details.
‘Thank you for coming in anyway, Tina,’ Murfin was saying as Fry walked in.
‘It’s not much use, is it?’
‘You did your best.’
‘I’m really sorry. I wanted to help.’
‘Don’t worry about it. But if you happen to remember anything else, you will let us know, won’t you?’
Fry turned, and saw Cooper, watching the waitress leave.
‘Didn’t she give us much?’ she asked.
‘I’ve only just got back myself. But Gavin says we ended up with something as vague as her descriptions were: a woman in her thirties, a man who could have been any age, because she hadn’t really taken much notice of him. It was Rose Shepherd herself that Tina remembers best.’
‘Two adults — one male, one female. Who could they have been? There aren’t many possibilities cropping up in the Shepherd enquiry so far. I suppose there’s either set of next-door neighbours, the Birtlands or the Ridgeways …’
‘Frances Birtland works in Matlock Bath,’ said Cooper. ‘She has a part-time job at the Masson Mill shopping village. But she’s well past her thirties.’
‘Still, it’s a connection of a kind. How far is it from Masson Mill to the tea rooms?’
‘Half a mile or so.’
‘Close enough for her to have nipped out for an hour.’
‘Her employer would have to cover for her, in that case.’
Fry nodded. ‘True. It’s getting a bit complicated for a chat over the teacups. And we’d have to place her husband in Matlock Bath, too. According to your interview report, his health isn’t too good.’
‘There
‘Who do you mean?’
‘Eric Grice and his sister. She lives in Foxlow. And Grice is the one person who knew Miss Shepherd and has actually been inside Bain House.’
‘You’re right,’ said Fry. ‘We ought to ask one or both of them what they were doing on Saturday, if only so we can eliminate them.’
‘We’ll have to wait to speak to the sister. Grice says she’s in Jersey.’
‘What did you make of this handyman? Do you think he was telling the truth?’
