Sachs offered grimly, “I got it wrong. There’re two perps.” She explained about her erroneous assumption. “I was following the sniper. The man who killed Lydia Foster’s somebody else.”

“Who do you think?” Cooper asked.

“Bruns’s backup.”

“Or a specialist hired by Metzger to clean up,” Laurel said. It seemed to Sachs that her voice brightened at this. Good news for the case, good news for the jury—that their primary suspect would order one of his officers to do something so heartless. Not a word of sympathy for the victim, not a frown of concern.

Sachs truly hated the woman at this moment.

She continued, pointedly speaking only to Mel Cooper, “Lon’s agreed to keep it a motive-unknown case for the time being—like the IED at the Java Hut’s still officially a gas main explosion. I thought it was better not to let Metzger know how the investigation’s going.”

Laurel was nodding. “Good.”

Sachs stared at the whiteboards then began to revise them in light of what they’d learned. “Let’s give Lydia Foster’s killer the title Unsub Five Sixteen. After today’s date.”

Laurel asked, “Anything more about the ID of the shooter, the man you followed to NIOS?”

“No. Lon’s got a surveillance team on him. They’ll call as soon as they make an ID.”

Another pause. Laurel said, “I’m just curious: Did you think about getting his fingerprints?”

“His—”

“When you were following the sniper downtown? The reason I’m asking is I was working a case once and an undercover detective dropped a glossy magazine. The subject picked it up for her. We got his prints.”

“Well,” Sachs said evenly, “I didn’t.”

Because if I had done that we’d have his fucking ID by now. Which we don’t.

An impenetrably cryptic nod from Laurel.

Just curious…

That was as irritating as “if you don’t mind.”

Sachs turned away from her, wincing slightly, and handed off the evidence from the Lydia Foster crime scene to Mel Cooper, who regarded the slim pickings with the same dismay that Sachs felt.

“That’s it?”

“Afraid so. Unsub Five Sixteen knows what he’s doing.” Sachs was looking at the photos of Lydia Foster’s bloody corpse, which she was downloading from the crime scene team in Queens and printing out.

Lips tight, she stepped to one of the whiteboards and taped the pictures up.

“He tortured her,” Laurel said softly but with no other reaction.

“And took everything Lydia had about the assignment for Moreno.”

“What could she have known?” the ADA wondered. “If he had a commercial interpreter with him on the business trip, he obviously wasn’t taking her to meet criminals. She’d be a good witness to testify that Moreno wasn’t a terrorist.” She added, “That is, would have been a good witness.”