I had no idea who he was. I didn’t make the connection till two days ago, when the first police sketches began circulating.

Manning has come to full nuclear alert. His glance to me says, Make sure you’re recording every syllable.

Ellie Landau tells Manning that she had flown to Moscow to assist in the defense of Alexsandr Golokoff, who was facing a hearing before a Kremlin tribunal. The Sabbath, she says, fell on the night before. Ellie was at shul in a private home. In attendance, she says, were a dozen or so, all Russians, friends of Mr. Golokoff.

ELLIE LANDAU

Instancer was among them. He sat alone. He spoke to no one, and no one seemed to know him. He was wearing a yarmulke and a prayer shawl. I was struck by him because of his appearance.

Manning presses Ellie to be more specific.

ELLIE LANDAU

He was electrifying. Charismatic. I couldn’t tear my eyes off him.

Ellie Landau tells Manning that Golokoff—“your ‘Russian victim number two’”—was supposed to meet her there, that night, at the private home.

ELLIE LANDAU

But he never showed. When I got back to my hotel I saw on TV that he had been murdered. I knew instantly that this young man was the killer. He showed up at shul, I felt certain, out of some diabolical intention to let me know. He knew who I was. He was mocking me.

Manning asks Ellie Landau what conclusion she draws from this encounter. If her supposition about Instancer being Golokoff’s killer is true, what does she believe it means? He’s a hired assassin? An FSB agent? A religious nut?

ELLIE LANDAU

I believe what you believe, Detective. We both know who he is.

Ellie Landau’s car pulls in at the curb and stops. Time is 1930, seven-thirty in the evening. The driver springs out and scurries around to open the right rear door. Ms. Landau is about to step out from beneath the awning.

Her phone pings with an incoming text.

Ellie checks it.

It’s a video.

Ms. Landau taps the PLAY arrow.

She reacts with dismay.

MANNING

What?

Ellie Landau stares at her phone in alarm.

Manning steps in to see.

ELLIE LANDAU

This is live! It’s happening right now . . .

On Ellie Landau’s screen a video streams.

It’s Instancer.

On a subway platform somewhere.

He’s wearing the same jeans, T-shirt, and hoodie he wore at the Rebbe’s.

The video is a selfie.

He’s filming himself.

In chalk, on a steel subway column, Instancer finishes scratching the last of twenty-seven vertical marks, in five groups of five, with horizontal slashes to mark the fifth in each, then two more verticals to complete the tally.

INSTANCER

(on video, speaking to camera)

Twenty-seven down out of thirty-six. Twenty-eight coming up.

Instancer grins. The video goes dark.

MANNING

Where is he? Wind the video back!

Ellie Landau obeys.

Manning peers.