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.’

CHAPTER 9

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?’