“I don’t know. I only know who he’s not. Not Jaeger.” Jaeger hadn’t operated like this, killing innocents for his own convenience. The warehouse clerk, all those people on the streets between them, the family in the train carriages. Abuelo, for that matter, and the household there. Jaeger had known who Drake was, called him by name. But he’d never hurt anyone else to get to him.

Professional, Hall had said. Opposite numbers. But it hadn’t been personal.

Yet it had been Jaeger’s voice on the phone. He was involved. Somehow.

Margot’s fingers slid free of his, and she wandered through the small, three-room flat. For a moment, Drake just watched her unique way of wandering. She didn’t do it aimlessly like other people. She wandered with precision. Two steps, a halt, a three-hundred-sixty degree turn. Two more steps, another halt, another turn. Taking in everything. Seeing numbers, probably, to account for everything. Boards in the floor. Books on the shelf. Pillows on the bed. Slices of bread on the plate on the table, where Walsh or whatever his name really was must have been sitting down to eat when the police had knocked on his door.

Not his door. Williams’s door.

Drake moved, too, after a minute. Less precisely, but perhaps more purposefully. He was no stranger to poking about, finding information, investigating. The police had said they’d taken nothing with them, that there was nothing to give them a clue as to the killer’s identity. Nothing, they insisted, to indicate that the man living here was even Williams’s killer rather than a random squatter.

He knew better. Drake opened every drawer, checked every loose board, pulled out every book.

“Margot.” The volume in his hands was in German, but he recognized a few of the words. It was a guide on the game Go. And it had telltale yellow papers sticking out of its pages like bookmarks.

She appeared at his side and drew in a sharp breath. “Telegrams.”

“Telegrams.” He opened to the first one, made note of the page number in case it mattered, and handed it to her after only a cursory glance. “In German.”

“In code.” She sank onto the edge of the little wooden chair by the bookshelf. “Blast.”

“What?”

“In the mystery code. I’m all but certain of it. The one we haven’t broken yet.”

He extracted the others too. “What about these?”

She took them, her eyes going over them not word by word but seeming to swallow them whole. Then she let her eyes slide shut, her lips move without sound. And she nodded. “All the same.”

Drake re-marked the pages in the book with pieces he tore off a blank page on the desk. “How long will it take you to break it?”

“Too long. Weeks. Months. We don’t have enough examples of it.”

“Not even when combined with what you have on file?”