He showed his shield to one of the guards, signed in, got a temporary ID, then made his way across the echoing expanse, past the dinosaurs, past another checkpoint, through an unmarked door, and down a series of labyrinthine back corridors to Central Security — a journey he remembered all too well. A uniformed guard sat, alone, in the waiting area. As D’Agosta entered, he jumped to his feet.

“Mark Whittaker?” D’Agosta asked.

The man nodded rapidly. He was short — about five foot three — and portly, with brown eyes and thinning blond hair.

“Lieutenant D’Agosta, homicide. I know you’ve been over all this before, and I’ll try not to take up more of your time than necessary.” He shook the man’s limp, sweaty hand. In his experience, private security guards were one of two types — wannabe cops, resentful and pugnacious, or mild-mannered door shakers, cowed and intimidated by the real McCoy. Mark Whittaker was definitely of the latter breed.

“Can we chat at the crime scene?”

“Sure, yes, of course.” Whittaker seemed eager to please.

D’Agosta followed him on another lengthy journey back out of the bowels and into the public areas of the Museum. As they walked through the winding corridors, D’Agosta couldn’t help glancing at the exhibits. It had been years since he’d set foot in this place, but it didn’t seem to have changed much. They were walking through the darkened, two-story African hall, past a herd of elephants, and from there into the Hall of African Peoples, Mexico and Central America, South America, hall after echoing hall of cases full of birds, gold, pottery, sculpture, textiles, spears, clothing, masks, skeletons, monkeys… He found himself panting and wondering how the hell it was he could hardly keep up with this fat little guard.

They made their way into the Hall of Marine Life and Whittaker finally came to a stop at one of the more distant alcoves, which had been sealed off with yellow crime scene tape. A Museum guard stood before the tape.

“The Gastropod Alcove,” D’Agosta said, reading the name off a brass plaque that stood beside the opening.

Whittaker nodded.

D’Agosta showed his shield to the guard, ducked under the tape, and motioned Whittaker to follow. The space beyond was dark and the air dead. Glass cabinets covered the three walls of the alcove, stuffed full of shells of all sizes and shapes, from snails to clams to whelks. Waist-high display cases, sporting still more shells, stood before the cabinets. D’Agosta sniffed. This had to be the least-visited place in the entire damn Museum. His eye fell on a queen conch, pink and shiny, and for a moment he was transported back to one particular evening on the North Shore of Hawaii, the sand still warm from the just-departed sun, Laura lying beside him, the creamy surf curling around their feet. He sighed and hauled himself back to the present.

He glanced below one of the display cases, where a chalk outline and several evidence tags were visible, along with a long, long rivulet of dried blood. “When did you find the body?”

“Saturday night. About eleven ten.”

“And you came on duty at what time?”

“Eight.”

“This hall was part of your normal shift?”

Whittaker nodded.

“When does the Museum close on Saturdays?”

“Six.”

“How often do you patrol this hall, after hours?”

“It varies. The rotation can be anywhere from half an hour to every forty-five minutes. I have a card I have to swipe as I go along. They don’t like us to make our rounds on a regular schedule.”

D’Agosta took out of his pocket a floor plan of the Museum he had grabbed on the way in. “Could you draw on here your rounds of duty or whatever you call it?”

“Sure.” Whittaker fumbled a pen out of his pocket and drew a wandering line on the map, encompassing much of the floor. He handed it back to D’Agosta.

D’Agosta scrutinized it. “Doesn’t look like you normally go into this particular alcove.”

Whittaker paused for a moment, as if this might be a trick question. “Not usually. I mean, it’s a cul-de-sac. I walk past it.”

“So what made you look into it at eleven PM last night?”

Whittaker dabbed at his brow. “The blood had run out into the middle of the floor. When I shone my light in, the… the beam picked it up.”

D’Agosta recalled all the blood from the SOC photographs. A reconstruction of the crime indicated that the victim, an older technician named Victor Marsala, had been bludgeoned over the head with a blunt instrument in this out-of-the way alcove, his body stuffed beneath the display case, minus watch, wallet, and pocket change.

D’Agosta consulted his tablet. “Any special events going on yesterday evening?”

“No.”

“No sleepovers, private parties, IMAX shows, after-hours tours? Things of that nature?”

“Nothing.”

D’Agosta already knew most of this, but he liked to go over familiar ground with a witness, just in case. The coroner’s report indicated that the time of death had been around ten thirty. “In the forty minutes leading up to your discovery of the body, did you see anyone or anything unusual? A tourist after hours, claiming to be lost? A Museum employee out of his or her normal working area?”

“I didn’t see anything odd. Just the usual scientists and curators working late.”

“And this hall?”

“Empty.”

D’Agosta nodded out past the alcove, toward a discreet door in the far wall with a red EXIT sign over it. “Where does that lead?”

Whittaker shrugged. “Just the basement.”

D’Agosta considered. The South American gold hall wasn’t far away, but it hadn’t been touched, nothing had been stolen or disturbed. It was possible Marsala, on his way out after completing a late-night assignment, had disturbed some bum, taking a catnap in this desolate corner of the Museum, but D’Agosta doubted the story was even that exotic. What was unusual about the case was that the killer had apparently managed to leave the Museum without notice. The only way out at that time of the night was through a heavily guarded checkpoint on the lower level. Was the killer a Museum employee? He had a list of everyone working late that night, and it was surprisingly long. Then again, the Museum was a big place with a staff of several thousand.

He asked Whittaker a few more perfunctory questions, then thanked him. “I’m going to look around, you can head back on your own,” he said.

He spent the next twenty minutes poking around the alcove and adjoining areas, regularly referring to the crime scene photos on his tablet. But there was nothing new to see, nothing to find, nothing that appeared to have been overlooked.

Fetching a sigh, D’Agosta stuffed the iPad back into his briefcase and headed off in the direction of the public relations department.

Observing an autopsy ranked low on the list of Lieutenant Peter Angler’s favorite activities. It wasn’t that he had a problem with the sight of blood. In his fifteen years on the force, he’d seen more than his share of dead bodies — shot, stabbed, bludgeoned, run over, poisoned, pancaked on the sidewalk, cut in pieces on the subway tracks. Not to mention his own injuries. And he was no shrinking violet: he’d drawn his gun in the line of duty a dozen times and used it twice. He could deal with violent death. What made him uneasy was the cold, clinical way in which a corpse was systematically taken apart, organ by organ, handled, photographed, commented on, even joked about. That and, of course, the smell. But over the years he’d learned to live with the task, and he approached it with stoic resignation.

There was something about this autopsy, however, that gave it a particularly macabre cast. Angler had seen a lot of autopsies — but he’d never seen one that was being keenly observed by the victim’s own father.

There were five people in the room — living people, anyway: Angler; one of his detectives, Millikin; the forensic pathologist in charge of the autopsy; the assisting diener, short and shriveled and hunched like Quasimodo — and Special Agent Aloysius Pendergast.