When he'd been head of IRD--the Investigation and Resources Division of the NYPD, the forensic unit--Rhyme had walked everywhere in New York City. He carried small bags and jars in his pockets for the samples of soil and concrete and dust and vegetation he'd collect to add to his knowledge of the city. A criminalist must know his territory in a thousand different ways: as sociologist, cartographer, geologist, engineer, botanist, zoologist, historian.
He realized that there was something familiar about the trace that Cooper was describing. But what?
Wait, there's a thought. Hold on to it.
Damn, it slipped away.
"Hey, Loaban?" a voice called, but from a distance. Rhyme ignored Li and continued to walk intently through, then fly over, the various neighborhoods of the city.
"Is he--?"
"Shhhhh," Sachs said firmly.
Freeing him to continue on his journey.
He sailed over the Columbia University tower, over Central Park with its loam and limestone and wildlife excrement, through the streets of Midtown coated with the residue of the tons of soot that fall upon them daily, the boat basins with their peculiar mix of gasoline, propane and diesel fuel, the decaying parts of the Bronx with their lead paint and old plaster mixed with sawdust as filler . . . .
Soaring, soaring . . .
Until he came to one place.
His eyes opened.
"Downtown," he said. "The Ghost's downtown."
"Sure." Alan Coe shrugged. "Chinatown."
"No, not Chinatown," Rhyme replied. "Battery Park City or one of the developments around there."
"How'd you figure that out?" Sellitto asked.
"That montmorillonite? It's bentonite. That's a clay used as slurry to keep groundwater out of foundations when construction crews dig deep foundations. When they built the World Trade Center they sunk the foundation sixty-five feet down to the bedrock. The builder used millions of tons of bentonite. It's all over the place down there."
"But they use bentonite in a lot of places," Cooper pointed out.
"Sure, but the other trace materials Sachs found are from there too. That whole area is landfill and it's full of rusted metal and glass trace. And the ash? To clear the old piers down there the builders burned them."
"And it's only twenty minutes from Chinatown," Deng pointed out.
Thom wrote this on the evidence chart.
Still, it was a huge area and contained many high-density buildings: hotels, apartments and office buildings. They would need more information in order to narrow down exactly where the Ghost might be staying.
Sonny Li was pacing, walking in front of the board.
"Hey, Loaban, I got some ideas too."
"About what?" Rhyme grumbled. The man reeked of cigarette smoke. Rhyme had never smoked but he felt a huge burst of crip envy--that this man could partake in his vices all by himself, without having to track down a conspirator to help him.
Fucking surgery better do something, he thought.
"Hey, Loaban, you listening?"
"Go ahead, Sonny," Rhyme said, distracted.
"I was at crime scene too."
"Yeah," Sachs said, giving him an exasperated look. "Walking around, smoking."