He picked up the remote to turn the TV on, presumably to see the news. Pam took the chance to leap from the couch, shoving him back hard. When he stumbled back she sprinted for the door. But she got no more than two steps before he tackled her. She went down hard, her face bouncing on the wood. Pam tasted blood from a split lip. He grabbed her by the collar and dragged her roughly back to the couch, virtually tossing her onto it.

‘Never do that again.’ Leaning close, he dipped his finger in her blood and drew something on her face.

Whispering, he told her, ‘Body markings’re windows, you know. Into who you are and what you’re feeling. In some Native American tribes using paint – which is just a temporary tattoo – was a way to tell everybody what you were feeling. Warriors couldn’t express emotion through words or facial expressions – not part of the culture – but they could use painted mods to show they were in love or sad or angry. I mean, even if you lost a child, you couldn’t cry. You couldn’t react. But you could paint your face. And everyone knew how sad you were.

‘On your face, just now? I wrote the marks that mean Happy in the Lakota tribe.’

Then he reached into his backpack and took from it a roll of duct tape and a portable tattoo gun.

When he did this, his sleeve tugged up and Pam found herself staring at a tattoo. It was red. She couldn’t see it all but the portion exposed was the head and upper body of a centipede, whose all-too-human eyes stared at her just as Seth’s did now: The look was of hunger and disdain.

‘You’re the one tattooing those people,’ Pam said, her voice a frail whisper. ‘Killing them.’

Seth didn’t respond.

‘How do you know that couple? The terrorists?’

‘I’m their nephew.’

Seth – but no, not Seth; he’d have a different name – was assembling his tattoo gear. She stared at his arm, the tattoo. The insect eyes stared back.

‘Oh, this?’ He tugged his sleeve all the way up. ‘It’s not a tat. It’s just a drawing – water-soluble ink. The sort some artists use to do outlines.’ He licked his finger and smeared it. ‘When I was the Underground Man – out on the prowl – I’d draw it on my arm. Took ten minutes. When I was your friend Seth, I’d wash it off. It only had to be good enough to let witnesses see it and for your police friends – and you – to be happy that the new man in your life, me, wasn’t the killer.’

Pam was crying.

‘Lip hurt? You tried to run.’ He shrugged. ‘A busted lip is nothing compared with—’

‘You’re insane!’