And—from videos posted by the school and the PTO—I learnedwhat the school visitors’ passes look like, not high definition, but sufficient to duplicate into a reasonable facsimile. I discovered the controversy within the parent-teacher organization.

Sitting back and watching the videos for hour after hour after hour, I can see the types of locks and deadbolts and alarms people have. I can see who has dogs and door bars, I can see who keeps a shotgun nearby (rare in New York City but occasionally). I know where the knives are, and the toolboxes. I can see who has carpet—for silent stalking—and I can hear who lives on busy streets to cover up my noise (remembering the 2019 disaster, as always). I know the layout of every apartment before I approach. I know who has young children, who might need a bit of nursing or potty and might destroy my perfectly good evening.

I can even see who delivers the pizza (handbills stuck to the fridge with silly little magnets), who their doctors are, who has diabetes (insulin needle reminders), and who has a little too much love of the bottle.

I knew Carrie Noelle had the lunch date because she wrote it in red marker on a wall calendar.

People share so very much …

In college, I remember, I became fascinated with Darwin’s theory of natural selection.

People think it’s about ape-like creatures becoming humans. Ah, but the broader view about survival of the species is what so gripped me.

The theory is quite simple. It has four components:

One, individual creatures within a population differ.

Two, those differences are passed on from parents to their offspring.

Three, some of those individuals are more successful in surviving than others.

Four, those successful ones have survived because of traits that they have inherited and that they will in turn pass on to their subsequent generations. The unsuccessful die off.

In the wilderness, deer that are the color of the surrounding woods will tend to survive, while albino deer, which stand out to predators, will not.

This is exactly my worldview. People who don’t post anything online are invisible to threats like me. Those who do? Well, think of poor Annabelle Talese, the influencer, online day and night. And Carrie Noelle running her mini-QVC toy-shopping show out of her home and Taylor Soames and Roonie, who post in hopes of meeting mates or friends or because of ego or boredom or loneliness or … who knows why?

The difference is that by posting, theychooseto be the albino deer.

So that if the wolf, the coyote, the human hunter, were to take them as trophies, well, their deaths would really be of their own making.

This is simple logic to me.

45

The cause of death was asphyxia,” Mel Cooper reported to Rhyme.

Cooper, in the sterile portion of the parlor, was staring down at what was left of the corpse. Which was not of the human variety, but rather aMusca domestica, the common housefly discovered by Sachs in one of the Locksmith’s footsteps in the Bechtel Building.

The tech explained that it had perished because its muscles had frozen up in a state of tetany, which is essentially a nonstop contraction. It could neither fly nor breathe. The immediate cause for this was the blocking of acetylcholinesterase, an enzyme that allows the muscles to relax. The reason for the blockage of the multisyllabic enzyme was a particular organophosphate, a fancy name for insecticide.

Cooper continued, “The substances in the toxin are parathion, malathion, diazinon, terbufos.”

Amelia Sachs laughed. “Sounds like the names of the bad guys in a superhero movie.”

Rhyme had never seen a superhero movie but on the basis of that observation alone he thought he might give one a try, though he guessed his respect for logic and science and rational thought might dampen the careless treatment of the natural world that the filmmakers would rely on.

The insect’s demise had given them a lead, possibly, if not an earthshattering breakthrough. A search revealed that only one product contained the “bad guys” in the same proportions as those found in the dead fly. It was Fume-Assure, and it was used by large-scale fumigation companies, of which a half-dozen operated in Manhattan. One helpful executive, intrigued at being part of a police investigation, explained that that particular insecticide was used almost exclusively for fumigating old, unoccupied buildings, which would be renovated and put up for sale.

“You can’t tent in Manhattan but you seal the windows and doors. Pump this stuff in. Let it sit for a week then vent.”

“Apartment buildings? Offices?”

“Anything. High-rise, low-rise.”

In Rhyme’s mind, the chain went: The fly was found within the Locksmith’s footprint at the Bechtel Building. No one would have fumigated a building that was about to be torn down, so it was most likely that he had picked it up someplace else. Could that location be helpful? No way of knowing. But Rhyme decided to make the assumption that it was. Why not? The case wasn’t overflowing with leads. So, they would look for an old building that was unoccupied and up for sale. He wouldn’t live there, unless he was a squatter, which didn’t seem likely, but would have another connection with it. Maybe staking out the next victim.

Or perhaps, it now occurred to Rhyme, it was a building somehow related to his profession.