He was musing, ‘Feel bad about my cousin. Josh, poor Josh. A shame about him. The others? No worries there. My uncle was going to die soon. That was on the agenda. I was going to kill my aunt too as soon as we got back to Illinois. Blame them both on some homeless guy, an illegal probably. But once I saw the pressure in the pipes hadn’t been shut off, I knew Lincoln Rhyme had figured the plan out and I had to give them up. I left a note with the address of the hotel at the scene. That’s how Lincoln found them.’

He worked meticulously, filling the tube with the care of a surgeon, which he was, in a way, she reflected. The battery-powered tattoo gun was spotless. After he assembled the device he sat back and tugged her shirt up to below her breasts. He looked over her body, obsessed, it seemed, with her skin. She recoiled when he stroked her below the navel. As if the contact were not via his fingers but with the centipede’s crimson legs.

But there seemed nothing sexual about the touch. He was fascinated only with her flesh itself.

She asked, ‘Who was it? That you killed in the water tunnel?’

‘Hey, hold on there!’ Billy said.

Pam winced. Was he going to hit her?

‘I didn’t kill him. Your friend did. Lincoln Rhyme. He’s the one who made the announcement that the water pressure was shut off. But I was suspicious. So I got some insurance. I met a homeless man underground a few days ago. Nathan. One of the mole people. You ever heard about them? I thought it’d be helpful to use him. I gave him a pair of coveralls and did a fast tattoo of a centipede that matched mine, on his left arm. I knew where he hung out – near the Belvedere – so before I drilled into the pipe I found him.

‘I offered him a thousand dollars to help me drill a hole to help me test the water. He agreed. But’ – Billy shook his head – ‘I was right. The city was bluffing about cutting down the pressure. As soon as he drilled through the pipe, the stream of water cut him in half.’ He shivered. ‘There was nothing left of his head and chest. It was pretty tough to see.’

At least he had a spark of sympathy.

‘Knowing that that might’ve been me.’

Or maybe not.

‘That told me it was time to bail. The police’ll find out soon enough it wasn’t me but I’ve bought some time. Okay, time to bleed …’ Then he said something else. She couldn’t quite hear. It seemed to be ‘Oleander.’

He rose, looked her over. Then he bent down and gripped the button of her jeans. Pop, it opened and the zipper came down.