He called Nathan straight away. ‘Did this Dorothea or Thea woman have long silver-grey hair and beautiful bone structure,’ he said without preamble.

‘Definitely the hair. Can’t comment on the bone structure. Why, Tom? What’s—’

The phone went dead in Tom’s hand. ‘Shit!’

He picked up his other phone. ‘Becky, I’ll call you back. Don’t go anywhere. I need to speak to someone.’

He hung up and sat staring at his mobile. Why the hell had his conversation been cut short? He tried again, but it didn’t connect.

Tom was about to call Becky back when his personal mobile rang again.

‘What happened? Why did we get cut off?’

‘I’ll put Jack on,’ Nathan said.

‘Tom, there’s something weird going on. We’re outside the house. We came up with a plan, and we were heading up the drive while Nathan was talking to you and his mobile went dead. So did mine. I think there’s a signal jammer operating.’

‘Maybe just a dead patch. Why would you think it’s a jammer?’

There was a small sigh. ‘I wrote an app for my phone. It pings when there’s a sudden loss of signal. It’s helpful to know if you’re walking into trouble.’

Tom said nothing. There was nothing to say.

‘I’ve tried walking up the drive a couple of times and it pings each time. There’s a full signal at the gate and then nothing. It’s more than a dead spot – I’ve moved around a bit to check it out. I’m telling you, it’s a jammer. Now why would an elderly couple do that? How would they know how to do that?’

‘What’s the address?’

Jack told him, and Tom scribbled it down while speaking quickly to his brother, hoping that for once he would listen.

‘I want you both to stay out of there. Seriously, I think there’s more to this than we already know, and if I’m right, I don’t want you to alert anyone. Can you do that?’

‘I suppose so. The house looks quiet. No lights on anywhere. Even though it’s not fully dark yet, I would have expected a few lamps on at least. Maybe they’re out.’

‘Well keep well away from the entrance, in case they come back and find you two skulking around in the undergrowth. Understood?’

‘Okay, okay. And I promise not to break in.’

Tom sighed with exasperation and Jack laughed.

‘Oh, and as we were driving here I accessed iMessage on Hannah’s laptop and found an interesting text she’d sent to her employers. I’ll forward it to you. Make of it what you will.’

Tom hung up and called Becky. She picked up straight away.