A Textbook Case

sheer number of samples?
    Hence, the call to Marko.
    Who had connections in the forensic science department at the police academy. Rhyme had asked the young man to get his professors’ okay to enlist the rookies to help, with Marko supervising. Although there were hundreds of samples, because so many students were helping, each one had no more than five or ten. They were to look for the smallest samples, on the assumption that the largest quantities were materials that the unsub had intentionally flooded the scene with.
    For hours there’d been no discoveries. But an hour ago Marko had called the townhouse.
    “Detective Rhyme, sir?”
    Rhyme didn’t bother to correct him on the appellation. “Go on.”
    “We might’ve found something. We did what you said and prioritized everything according to quantity, then concentrated on the smallest trace. The least common was some vegetation that contained traces of urushiol.”
    “The toxin in poison ivy or sumac,” Rhyme had blurted.
    Sachs had wondered, as she often did, How does he
know
that?
    “Yessir. And it’s in poison oak, too.”
    “No, forget that. You don’t see it much in Manhattan. We’ll stick with ivy and sumac.”
    Marko had added that that vegetation was attached to bits of flower petals. They’d absorbed small amounts of glyphosate—”
    “An herbicide used to
kill
poison ivy and sumac.”
    “Yessir,” Marko said again. “So the perp might’ve spent time in a flower garden that was recently treated for the toxic plants.”
    He added another discovery: “They also found trace fragments of bovine bone dust in the soil attached to the vegetation.”
    “West Village,” Rhyme had pronounced. “Runoff, rains, rats… they carry all sorts of goodies from the meat-packing district, including beef bone dust.”
    He’d had Sellitto start a hunt in city parks in the western part of Greenwich Village, any that had flower gardens. “But only the ones that’d been recently treated for poisonous plants.”
    And the results of that search led here, to where Sachs was now standing, on West Tenth Street. The small park, about three blocks from the meat-packing district, was surrounded by three-, four- and five-story townhouses and brownstones, nearly all of them apartments.
    Rhyme had explained their find to Sellitto, who’d ordered the sweep in the area, telling the patrol officers to pay attention to laundry rooms, kitchens and storerooms, since the other category of evidence in play was domestic cleaning supplies.
    “Long shot,” the detective had muttered.
    “It’s the only shot we’ve got.”
    It was now 10:30 p.m. and the officers had been canvassing for half an hour.
    Many citizens were reluctant to open their doors, even for police, or someone
claiming
to be police. Language was always a barrier and, even once they were admitted, the officers often had to try to survey individual units, since some buildings did not have communal laundry rooms.
    Sachs watched a team storm into a brownstone. She stared; was this the site?
    They came out a few minutes later, shaking their heads.
    “Anything?” Rhyme asked her urgently.
    “No.”
    Sachs’s fingers disappeared into her mass of hair and dug obsessively into her scalp. Stop it, she told herself.
    Deal with the tension.
    She dug some more.
    The lead would only be helpful if it led to another crime in progress. If the trace led to Unsub 26’s apartment and the police knocked on the door, he might open it, smile and say, “No sir, I never heard of a Jane Levine. You have a nice night now.”
    Sachs looked past the flashing lights and saw Marko, in jeans and a dress shirt, running shows. He caught her eye, gave a brief nod of recognition and then turned back to the scene, as if studying it intently for future reference. He was holding a scene suit bag. Let’s hope he gets a chance to use it, she thought.
    Then her radio crackled, a woman’s voice. “Portable seven-six-six-three. I’ve got something.”
    “Go ahead,” Sachs said, identifying herself as a detective.
    The patrol officer explained she was at an address a block away, on West Tenth. “We’ve got an incendiary IED and victim nearby, immobilized. We need the Bomb Squad.”
    “I’m on my way,” Sachs told her and began to run. Then into her mouthpiece radio: “Got a hit, Rhyme,” she told him and, struggling to ignore the pain in her knees, sprinted faster. Marko was following, as were several other officers.
    “Tell