The Commandments speculated that Rhyme would then think: What if the poisoned tattoos were about something other than random killings by a psychotic?

They’d analyze the numbers in the tattoos and would come up with the flood in Genesis. He’d intentionally inked the tattoo artist in the Village with “the six hundredth” last, because it would have been too easy to find the flood passages in the Bible if he’d given them in proper order.

In the six hundredth year of Noah’s life, in the second month, on the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. And the rain was upon the earth forty days and forty nights …

So domestic terrorists had returned to plant bombs to re-create the flood and wash away the sin of this Sodom.

Rhyme and Sachs would brainstorm about where the bombs might be and realize that, yes, of course, they were in the batteries for the crime scene lights. Since they might go off at any time and it would take awhile for the Bomb Squad to break through the sealed cases and render-safe, or extract the IEDs, the Department of Environmental Protection would take the drastic but necessary step of shutting the massive gates of Water Tunnel 3’s Midtown valve, squelching the supply of water flowing to the pipe Billy was now walking beside.

As soon as that happened the pressure in the pipe would drop to nearly nothing.

Which would allow him to drill a one-thirty-second-inch hole through the iron – a feat impossible when the line was active because the pressure would force the water out of the hole at the speed and with the cutting force of an industrial laser.

With the pressure off he could then inject into the water supply pipe what he’d brought with him here, in the metal thermos. The last poison of the Modification.

Botulinum, a neurotoxin produced by the bacterium Clostridium botulinum, is the most poisonous substance on earth. A half teaspoon could easily kill the entire population of the United States.

While it is generally very difficult to come by the more toxic substances in the world – say, radioactive poisons such as polonium and plutonium – botulinum is surprisingly available.

And we have vanity to thank for that.

The bacteria are the basis for Botox, a muscle relaxant to relieve spasticity. It’s mostly known, though, for cosmetic treatments to smooth skin (its toxic qualities inhibit a neurotransmitter that creates wrinkles).

The stockpiles of the spores are carefully guarded but Billy had located a source and broken into a cosmetic surgical supply company in the Midwest. In addition to a good selection of drugs and medical gear, he’d managed to steal enough spores to create a botulinum factory, which had been silently – and airlessly – producing a stockpile of the bacteria and the toxin and more spores.