The CS tech cop nodded greetings to Eagleston and her partner, who like him were based in the massive NYPD crime scene oper ation in Queens. Despite the ornery weather and a chill in the parlor, Cooper wore a short sleeved white shirt along with baggy black slacks, giving him the appearance of a crusading Mormon elder or high school science professor. His shoes were Hush Puppies. People usually weren’t surprised to learn that he lived with his mother; the astonishment came when they met his towering and beautiful Scandinavian girlfriend, a professor at Columbia. The two were champion ballroom dancers.

Cooper, in a lab coat, latex gloves, goggles and mask, gestured to an empty evidence examination table. His colleagues set the cartons on it and nodded goodbye, then went out once more into the storm.

‘You too, rookie. Let’s see what we’ve got.’

Ron Pulaski pulled on similar protective gear and stepped up to the table to help.

‘Careful,’ Rhyme said unnecessarily, since Pulaski had done this a hundred times and no one was more careful than he with evidence.

But the criminalist was distracted; his thoughts returned to Amelia Sachs. Why wasn’t she calling? He remembered seeing the powder pour into the video camera lens at the same time it hit her face. Remembered her choking.

And then: a key in the door.

A moment later. Wind. A cough. A throat clearing.

‘Well?’ Rhyme called.

Amelia Sachs turned the corner of the parlor, pulling her jacket off. A pause. More coughing.

‘Well?’ he repeated. ‘Are you all right?’

Her response was to guzzle a bottle of water that Thom handed to her.

‘Thanks,’ she said to the young man. Then to Rhyme: ‘Fine,’ her low sultry voice lower and sultrier than normal. ‘More or less.’

Rhyme had known that she hadn’t been poisoned. He’d spoken to the EMT who specialized in toxins as she’d been shepherded to Manhattan General Medical Center. Her symptoms were atypical for poisoning, the med tech had reported, and by the time the ambulance got to Emergency, her only symptoms were a racking cough and teary eyes, which had been flushed several times with water. The unsub had created a less than lethal trap – but the irritant might have blinded her or played havoc with the lungs.

‘What was it, Sachs?’

She now explained that swabs of mucous membranes and a lightning fast blood workup had revealed that the ‘poison’ was dust composed mostly of ferric oxide.

‘Rust.’

‘That’s what they said.’

Pulling the duct tape off an old metal armature to which the unsub had attached the flashlight had dislodged a handful of the stuff, which had poured into Sachs’s face.

As a criminalist, Rhyme was familiar with Fe2O3, more commonly known as iron (III) oxide. Rust is a wonderful trace element since it has adhesive properties and transfers readily from perp to victim and vice versa quite readily. It can be toxic but only in massive quantities – more than 2500 mg/m^3. It’s presence seemed to Rhyme didn’t smell weaponized. He instructed Pulaski to call the city works department to find out if ferric oxide dust was common in the tunnels.

‘Yep,’ the young officer reported after he’d hung up. ‘The city’s been installing pipes throughout Manhattan – because of the new water tunnel. Some of the fixtures they’re cutting away are a hundred and fifty years old. End up with a lot of dust. All their workers’re wearing face masks, it’s so bad.’

So the unsub had just happened to pick one of those fixtures to mount the flashlight to.

Sachs coughed some more, drank another gulp or two of water. ‘I’m pissed off I got careless.’

‘And, Sachs, we were  waiting for a phone call.’

‘I tried. The lines were out. One of the EMS techs said it was an Internet problem that’s also screwing up the phone switches. Been happening for the past couple of days. Some dispute between the hardwire cable companies and the new fiber optic ones. Turf wars. Even talking sabotage.’

Rhyme’s look said, Who cares?

With another faint, alto cough Sachs suited up for the lab and walked to the evidence cartons.

‘Let’s get our charts going.’ Rhyme nodded at the cluster of large whiteboards, standing about like herons on their stalky legs. They used these to list the evidence in a case. Only one was filled: the case of the recent mugging turned homicide near City Hall. The man who’d shaved so carefully for his date before stepping out into the street to be robbed and killed.

Sachs moved that board to the corner and pulled a clean one front and center. She took an erasable marker and asked, ‘What do we call him?’

‘November fifth’s today’s date. Let’s stick with our tradition. Unknown Subject Eleven Five.’

Sachs coughed once, nodded, then wrote in her precise script:

237 Elizabeth Street

Victim: Chloe Moore

Rhyme glanced at the white space. ‘Now let’s start filling it in.’

Before they could get to the evidence, though, the doorbell hummed once more.

With the familiar howl of wind and Gatling gun of falling ice, the door opened and closed. Lon Sellitto walked into the parlor, stomping his feet and missing the rug.

‘Getting worse. Man. What a mess.’

Rhyme ignored the AccuWeather. ‘The security videos?’

Referring to any surveillance cameras on Elizabeth Street, near the manhole that the perp had used to gain access to the murder site. And where he had apparently been spying on Sachs.

‘Zip.’

Rhyme grimaced.

‘But there was a witness.’

Another sour look from Rhyme.

‘I don’t blame you, Linc. But it’s all we got. Guy coming home from his shift saw somebody beside the manhole about ten minutes before nine one one got the call.’

‘Home from his shift,’ Rhyme said cynically. ‘So your wit was tired.’

‘Yeah, and a fucking tired witness who sees the perp is better than a fresh one who doesn’t.’

‘In which case he wouldn’t be a witness,’ Rhyme replied. A glance at the evidence board. Then: ‘The manhole was open?’

‘Right. Orange cones and warning tape around it.’

Rhyme said, ‘Like I thought. So he pops the cover with a hook, sets up the cones, climbs down, kills the vic and leaves.’ He turned to Sachs. ‘Moisture at the bottom of the ladder, you said. So he kept it open the whole time. What happened to the cones and tape?’

‘None there,’ Sachs said. ‘Not when I came out.’

‘He’s not going to be leaving them lying around nearby. Too smart for that. Lon, what’d your wit say about him, the perp?’

‘White male, stocking cap, thigh length dark coat. Black or dark backpack. Didn’t see a lot of the face. Pretty much the same descrip of the guy by the manhole when Amelia was running the scene underneath.’

The one peering at Sachs. Who’d escaped into the crowds on Broadway.

‘What about the evidence on the street?’

‘In that storm?’ Sachs replied.

Weather was one of the classic contaminators of evidence and one of the most pernicious. And at the scene near the manhole, there’d been another problem: The emergency workers’ footprints and gear would have destroyed any remaining evidence as they raced to get Sachs into the ambulance after the apparent poisoning from the trap that wasn’t.

‘So we’ll write off that portion of the scene and concentrate on underground. First, the basement of the boutique?’

Jean Eagleston and her partner had photographed and searched the basement and the small utility room that opened onto it but they’d found very little. Mel Cooper examined the trace they’d collected. He reported, ‘Matches the samples from the cellar. Nothing helpful there.’

‘All right. The big question: What’s the tox screen result? COD?’

They were starting with the assumption that the cause of death was poison but that wouldn’t be known until the medical examiner completed the analysis. Sachs had called and harangued the chief examiner to send over a preliminary report ASAP. They needed both the toxin and whatever sedative, as seemed likely, the perp had injected into Chloe to subdue her. Sachs had sealed the urgency by pointing out that they believed this murder was the start of a serial killing spree. The ME, she reported, had sounded as burdened as doctors generally do, especially city employee doctors, but he’d promised to move the Chloe Moore case to the front of the queue.