Then Sachs’s phone buzzed. The call was from Rodney Szarnek, with the NYPD Computer Crimes Unit, an elite group of thirty or so detectives and support staff. Although Rhyme was a traditional forensic scientist, he and Sachs had worked more and more closely with CCU in recent years; computers and cell phones—and the wonderful evidence they retained, seemingly forever—were crucial to running successful investigations nowadays. Szarnek was in his forties, Sachs estimated, but his age was hard to determine for sure. Szarnek projected youth—from his shaggy hair to his uniform of wrinkled jeans and T-shirt to his passionate love of “boxes,” as he called computers.

Not to mention his addiction to loud and usually bad rock music.

Which now blared in the background.

“Hey, Rodney,” Sachs now said, “could we de-volume that a bit. You mind?”

“Sorry.”

Szarnek was key to finding the whistleblower who’d leaked the STO. He was tracing the anonymous email with its STO kill order attachment, working backward from the destination, the Manhattan District Attorney’s Office, and trying to find where the leaker had been when he sent it.

“It’s taking some time,” the man reported, over a faint 4/4 rock beat of bass and drum. “The email was routed through proxies halfway around the world. Well, actually all the way around the world. So far I’ve traced it back from the DA’s Office to a remailer in Taiwan and from there to Romania. And I’ll tell you, the Romanians are not in a cooperating mode. But I got some information on the box he was using. He tried to be smart but he tripped up.”

“You mean you found the brand of his computer?”

“Possibly. His agent user string…Uhm, do you know what that is?”

Sachs confessed she didn’t.

“It’s information your computer sends out to routers and servers and other computers when you’re online. Anybody can see it and find out exactly what your operating system and browser are. Now, your whistleblower’s box was running Apple’s OS Nine two two and Internet Explorer Five for Mac. That goes back a long time. It really narrows the field. I’m guessing he had an iBook laptop. That was the first portable Mac to have an antenna built in so he could’ve logged into Wi-Fi for the upload without any separate modem or server.”

An iBook? Sachs had never heard of it. “How old, Rodney?”

“Over ten years. Probably one he bought secondhand and paid cash for it, so it couldn’t be traced back to him. That’s where he tried to be smart. But he didn’t figure that we could find out the brand.”

“What would it look like?”

“If we’re lucky it’ll be a clamshell model—they came two-toned, white and some bright colors, like green or tangerine. They’re shaped just what they sound like.”

“Clams.”