Rutledge put down the letter. What indeed to make of it? He agreed with Cummins that the author of the letter had purposely made the clues difficult to follow. Still, if Cummins had happened on that flint knife in the course of another case, would he have followed the same steps toward finding an answer? Was that the point, that the killer had felt he had done his duty, secure in the knowledge that his role would never come to light?

What’s more, were there clues in that letter that might lead to the name of the victim, if not the murderer?

Without the original, he wasn’t able to make an educated guess about that. But surely Cummins would examine all the possibilities?

Hamish said, “Ye canna see ye’re ain way. You canna’ worry oe’r much about the ins and outs of anither man’s inquiry.”

But Rutledge said, “It’s a puzzle. Like this one of Summers’s doing. God knows how long he has planned his revenge, but so far he’s carried it out without so much a qualm. The men he killed, the woman he took to France, the dog he’d abandoned.”

“If ye had never gone to yon hotel room at The White Swans, you wouldna’ ha’ known about yon dog.”

It was true. And the Dover police had been particularly interested in how he had known about the dog and how he had come to learn what it was called.

He’d replied simply that he had been several times to the hotel where the Pierces were staying. True, as far as it went.

Rutledge took a deep breath. “He’s coming back. I can feel it,” he said aloud into the silence of the room. “And sooner than we expect. And I don’t know how to stop him.”

Hamish said, “With any luck ata’, he’ll drown on his way back across yon Channel. I was never sea sick mysel’, but ithers were, and dying was a cheering thought.”

“But that’s the problem. He could come back through a dozen different ports.”

And hovering in the back of his mind was the inescapable knowledge that if he hadn’t believed the false lead to Brighton, he could have reached Dover in time.

Rutledge let it go. There was nothing he could do this night, and sometimes an answer came more readily if he ignored the problem.

He went out to find his dinner, choosing a restaurant where he wasn’t likely to encounter anyone from the Yard. The food there was edible, the clientele older and quiet, and he didn’t linger over his meal.

When he came home again, there was someone huddled in the doorway of the flat, only a thicker shadow among shadows.

His first thought was Summers. Or—his wife?

Bracing himself, he called, “Who is it? Who is there?”