But then Billy realized this was just another incident that proved the Rule of Skin true. No surprise here. He could be no more upset at this than a law of physics.

He gave a disappointed smile, walked around the man and kept moving.

‘Yo, I hook you up!’

A block east, Billy glanced behind him – he saw no one that was a threat – and stepped into a clothing store. He paid cash for a Yankees baseball cap and a pair of cheap sneakers. He tugged the hat on and swapped shoes. His old ones he didn’t throw out – concerned that the police might search the trash cans and find a pair of Bass with his prints on them – but when the clerk wasn’t looking he left one in a bin of discount shoes and the other on a rack, behind a row of similar footwear. He then stepped outside, striding fast toward his goal: the subway that would take him back to Canal Street, back to safety. Head down, once more, examining the congested sidewalks, filthy, marred with ovals of dog pee and dark dots of chewing gum, bordered with tired slush.

Yet no one looked at the coveralls, at the gear bag, no one glanced his way as if wondering: Is he the man who killed that girl in SoHo? The man who was nearly cornered and gunned down at the hospital in Marble Hill?

Walking fast once more, inhaling cold air rich with noxious exhaust. Of course he wouldn’t take the Number One train, which had a Marble Hill stop, because it was so close to the hospital. He’d spent days studying the New York City transit system. He was making for a station farther east, even if it meant a fast walk through unpleasant weather and amid more unpleasant people.

Yo, I hook you up …

And there were lots of them. The crowds were thicker now, more shoppers – taking advantage of the pre Christmas season to stock up on presents, he guessed. Dressed in dark clothing, worn and shabby.

Doctor Moreau’s Swine men, Dog men …

Some police cars sped past, heading toward Marble Hill. None of them paused.

Breathing hard, chest hurting again, he finally approached the metro entrance. Here the trains were not underground but elevated. He swiped his Metrocard and walked nonchalantly up the steep stairs and onto the platform, where he huddled as the damp wind sliced around him.

He pulled his cap lower, swapped the reading glasses for some with different frames, then pulled his gray scarf up around his mouth; the air was frigid enough so that this didn’t look odd.

Scanning for police. No flashing lights on the streets below, no uniformed officers in the crowds or on the platform. Maybe–

But wait.

He noted two men in overcoats about thirty feet away on the platform. One looked his way then turned back to his companion. They stood out here, being white and dressed in conservative clothing, white shirts and ties, under the bulky coats; most of the other passengers on the platform were black or Latino or mixed, and dressed much more casually.

Undercover cops? He had a feeling they were. They might not have been part of the actual manhunt – were here investigating a drug deal, maybe – but they’d heard the alert, and now believed they had the Underground Man.

One made a brief call and Billy had a feeling that it had been placed to Lincoln Rhyme. No basis for this, but instinct told him the cop was a friend and colleague of Rhyme’s.

A train was approaching but was still two hundred yards away. The men whispered something to each other and then walked his way, steadying themselves in the wind.

He’d been so careful, so smart in escaping from the doctors’ office building. Was he about to get caught because of a coincidence? Two cops who happened nearby.

Billy was nowhere near the exit. If he ran, he’d never make it in time. Could he jump?

No, twenty feet to the traffic filled street below. He’d break bones.

Billy decided he’d just have to bluff. He had a city employee ID, which would pass fast examination, but one call to downtown and they’d find out it was fake. He also had legitimate ID, which was, technically, a breach of the Commandments.

Thou shalt remain unidentifiable.

But, of course, that wouldn’t work. One radio or phone call and they’d find out who he really was.

He’d have to go on the offense. He’d pretend to ignore the men until they were right next to him and turn, smiling. Then he would shove one, or both, onto the tracks. He could escape in the chaos afterwards.

A messy plan. Clumsy and dangerous. But, he decided, there was little choice.

The men were getting closer now. Smiling but Billy didn’t trust that expression for a second.

The train was near now. A hundred feet away, eighty, thirty …

He looked for guns on the men’s hips, but they hadn’t unbuttoned their coats. He glanced toward the exit, judged timing and distance.

Get ready. The big one. Push him first. Lincoln Rhyme’s buddy.

The train was almost to the platform.

The taller of the two men, the one who was about to die first, nodded as he caught Billy’s eye.

Wait, wait. Give it ten seconds more. Eight, seven, six …

Billy tensed.

Four, three …

The man then smiled. ‘Eric?’

‘I’m, uhm, I’m sorry?’

‘Are you Eric Wilson?’

The train rushed into the station and squealed to a stop.

‘Me? No.’

‘Oh, hey, you look just like the son of a guy I work with. Sorry to bother you.’

‘No problem.’ Billy’s hands were trembling, his jaw too, and only partly from the cold.

The men turned and walked away, toward the train, which was now discharging passengers.

Billy walked onto the subway car, choosing a spot to stand that was close enough to the men to hear their conversation. Yes, he realized, they were just as they seemed to be – businessmen who’d finished some meeting uptown and were heading back to their office on Madison Avenue to write up some reports about how the meeting had gone.

Brakes released, and with a grind the train started south, rocking, squealing through the switches.

Soon they were in Manhattan, and diving beneath the surface. The Underground Man was in his world once again.

It had been a risk, taking the subway, but at least he’d minimized the danger. And apparently won. Rather than take the Number One train or the Number Four – the next one east – or even the B and D, he’d sped the several miles to the Allerton Avenue station, to catch the Number Two train. He’d assumed that someone – well, Lincoln Rhyme of course – might have ordered officers to the closer stations. But even the NYPD didn’t have the resources to search everywhere. He’d hoped his brisk pace would put him beyond the reach of a manhunt.

Apparently this was so.

As they sped south, Billy reflected: You’re not the only one who can anticipate, Captain Rhyme.

Mr 11 5 knows what he’s doing, Lincoln Rhyme reflected yet again, as he guided his Merits to the evidence examination table, where Mel Cooper and Sachs were examining the evidence from the hospital.

Despite her exhaustive search of the corridors, the doctors’ office building and the ‘skin museum’, the evidentiary findings from the abortive assault on Harriet Stanton were minimal.

There were no friction ridges; he’d been clever enough not to actually touch Harriet with his fingers (prints can be lifted off skin). He’d either gripped only her clothing or touched her flesh with his sleeves. And somewhere between fleeing the site of the attack in the basement and his slipping into the specimens room, he’d pulled on latex gloves (not vinyl, which display distinctive wrinkle patterns that can be introduced at trial).

But unlike the earlier scenes, he’d been taken by surprise, so he didn’t have the chance to don booties. Sachs got some good electrostatic footprints.

Size eleven Bass shoe, though that meant only that he was wearing a size eleven Bass shoe, not that he had size eleven feet.