But these basic facts about skin, as interesting as they were to Billy Haven, didn’t touch on its true value. Skin reveals, skin explains. Wrinkles report age and childbearing, calluses hint at vocation and hobby, color suggests health. And then there’s pigmentation. A whole other story.

Now Billy Haven sat back and surveyed his work on the parchment of his victim’s skin. Yes, good.

A Billy Mod …

The watch on his right wrist hummed. Five seconds later the second watch, in his pocket, did so too. Sort of a snooze alarm, prescribed by the Modification Commandments.

And not a bad idea. Like most artists, Billy tended to get caught up in his work.

He rose and, with illumination provided by the halogen headlamp strapped to his forehead, walked around the dim space underneath Provence2.

This area was an octagonal chamber, about thirty feet across. Three arches led to three darkened tunnels. In a different century, Billy had learned in research, these corridors had been used to direct cattle to two different underground abattoirs here on the West Side of Manhattan.

Healthy cows were directed to one doorway, sickly to another. Both were slaughtered for meat but the tainted ones were sold locally to the poor in Hell’s Kitchen or shipped down to Five Points or the city of Brooklyn, for the filthy markets there. The more robust cattle ended up in the kitchens of the Upper East  and Westsiders and the better restaurants in town.

Billy didn’t know which of the exits was for the healthy beef, which for the sickly. He’d been down both until they ended, one in brick, one in rubble, but he couldn’t deduce which was which. He wished he knew because he wanted to tattoo the young lady in the tainted beef corridor – it just seemed appropriate. But he’d decided to do his mod in the place where the livestock cull had been made: the octagon itself.

He looked her over carefully. The tattoo was good. The cicatrized border too. He was pleased. When he did a work for clients in his shop back home, Billy never worried about their reaction. He had his own standards. A job they seemed indifferent to might fill him with ecstasy. Or a girl could tearfully look over her wedding cake tattoo (yes, pretty popular) and cry at how beautiful it was but he’d see one flaw, a tiny stroke out of place, and Billy would be furious with himself for days.

This art was good, though. He was satisfied.

He wondered if they’d catch on to the message now. But, no, not even Lincoln Rhyme was that good.

Thinking about the difficulty he’d had earlier – at the hospital and the doctors’ office building – he’d decided it was time to start slowing down those pursuing him.

One of the passages in the Commandments, written in Billy’s flowing script, was this: ‘Continually reassess the strengths of the officers investigating you. It may be necessary to throw up roadblocks to their investigation. Aim for the lower level officers only; too senior, and the authorities will bring more effort to bear on finding you.’

Or, in Billy’s terms: Thou shalt smite all those who are trying to mess with the Modification.

His idea for slowing them down was simple. People who’ve never been inked think that machines use a hollow needle. But that’s not the case. Tattoo needles are solid, usually several soldered together, allowing the ink to run down the shaft and into the skin.

But Billy had some hypodermics, to sedate his victims. He now reached into his gear bag and withdrew a plastic medicine bottle with a locking cap. He opened the lid carefully and set the brown cylinder on the ground. He selected a surgeon’s hemostat, long tweezers, from his stash of stolen medical equipment. With this instrument he reached into the plastic bottle and picked up the three quarter inch tip of a thirty gauge hypodermic – one of the smallest diameters. He’d carefully fatigued this tip off the syringe and packed it with poison.

He now picked up the woman’s purse and worked the dull end of the needle into the leather under the clasp so that when the crime scene cop opened the bag, the business end of the nearly microscopic needle would pierce the glove and the skin. The tip was so thin, it was unlikely that the person pricked would feel a thing.

Until, of course, about an hour later, when the symptoms hit them like a fireball. And those symptoms were delicious: Strychnine produces some of the most extreme and painful reactions of any toxin. You can count on nausea, convulsion of muscles, hypertension, grotesque flexing of the body, raw sensitivity and finally asphyxiation.

Strychnine, in effect, spasms you to death.

Though in this case, the dosage would, in an adult, lead to severe brain damage rather than death.

Visit pestilence upon your pursuers.

A moan from behind him.

She was swimming to consciousness.

Billy turned toward her, the beam of the halogen whipsawing around the room, fast, leveraged by the motion of his head.

He carefully set the purse on the ground in a spot that looked as if he’d tossed it aside casually – they’d think it contained all sorts of good trace evidence and fingerprints. He hoped it would be Amelia Sachs who picked it up. He was angry at her for finding him at the hospital, even if Lincoln Rhyme was the one responsible. He’d hoped someday to go back to the specimens room but, thanks to her, he never could.

Of course, even if she didn’t get jabbed, maybe one of Lincoln Rhyme’s assistants would.

And Rhyme himself? He supposed it was possible; he’d learned that the man had regained some use of his arm and hand. Maybe he’d don a glove and pick up the purse. He definitely  wouldn’t feel the sting.

‘Oh …’

He turned to look at the art gallery of beautiful skin stretched out before him. Ivory. He taped a flashlight in place over his canvas, flicked it on. Looked at her eyes, squinting first in confusion, then in pain.

His wristwatch hummed.

Then the other.

And it was time to leave.

Lights flashed off the falling sleet, off the encrusted piles of old snow, off the wet asphalt.

Blue glows, white, red. Pulsing. Urgent.

Amelia Sachs was climbing out of her maroon Torino, parked beside several ambulances, though several ambulances weren’t necessary. None were. The only required medical vehicle was the city morgue van. The first responders to this scene reported that Samantha Levine, the unsub’s second victim, was deceased, declared dead at the scene.

Poison again, of course. That was the preliminary, from the first responders, but there was no doubt this was Unsub 11 5’s work.

When she hadn’t returned to the table of the chic restaurant Provence2, her friends had become concerned. A search of the restroom revealed an access door, which was slightly askew. A waiter had pulled it open, stuck his head in, gasped and vomited.

Sachs stood on the street, looking over the restaurant and the assembling vehicles. Lon Sellitto walked up. ‘Amelia.’

She shook her head. ‘We stopped him at the hospital this morning and he got somebody else. Right away. Telling us basically: “Fuck you.”’

Diners were settling checks and leaving and the staff were looking about as thrilled as you could imagine, upon learning that a patron had been abducted in the restroom and dragged into a tunnel beneath their establishment and murdered.

It was only a matter of time, Sachs guessed, before Provence2 would be shuttered. It was as if the restaurant itself were a second victim. She supposed the boutique on Elizabeth Street too would be out of business soon.

‘I’ll start canvassing,’ the big detective muttered and ambled off, digging a notebook from his pocket.

The crime scene bus arrived and nosed up to the curb. Sachs waved to the CS techs who were climbing out. Jean Eagleston was the lead, the woman who’d worked the Chloe Moore scene in SoHo – only yesterday though it seemed like last month. She had a new partner, a slim Latino who had calm but probing eyes – hinting that he was perfect for crime scene work. Sachs walked up to them. ‘Same procedure. I’ll go in first, process the body, walk the grid. You can handle the restroom where he snatched her, any exit routes.’