KARL AND I WALK GINGERLY from the Peabody Museum to a restaurant on Massachusetts Avenue. This is the interview he promised me when I broke the news to him. He uses two hands on the railing to ease himself down the Peabody stairs, heavily favoring his left leg.

It’s early December 2018, and Karl went skiing recently, he tells me. I’m surprised to hear it because he had made such a big show out of his retirement from the sport when we last met. Skiing was the one art he had mastered, not teaching, he had said. He seemed to miss it more than academia.

The day he decided to return to skiing, he’d had such a great time, he tried his luck again that same week. On the second run, he went into a turn, slightly lost his balance, and knew immediately what he had done. He felt his right knee pop and found himself on the ground. “I should not have done it. I’m eighty-one years old. C’mon!”

Karl had always known the dangers, he had told me when we last sat down. But he always felt safe: not that it couldn’t happen to him, but that it wouldn’t.

It happened to him three weeks ago, right when I called him about a break in the case. I’m about to press him on whether there was any cause-and-effect connection between the two events when he changes the subject entirely at the crosswalk by Annenberg, the freshman dining hall.

“I’ve given some thought to the solution,” Karl says, about Sumpter I suppose. I search his face, but it gives nothing away. “You know. I have an argument with David Reich,” he continues.

I have no idea where he’s going with this. “I don’t know who that is,” I say.

Karl explains that David Reich is a Harvard geneticist who analyzes ancient DNA to map out the migration patterns of humans thousands of years ago.

“Here’s the crux,” Karl says. “The DNA studies are in many ways in direct conflict with the archaeological record.”

Reich’s work, I later learn, is controversial. Critics fault him for drawing broad conclusions that overhaul our sense of the ancient world, based on apparently paltry evidence, like the DNA from just four skulls. They accuse his attempts to remodel our understanding of the world with science of falling prey to the same problems that oversimplified previous historical narratives. In our eagerness to find answers and simple through-lines, we overlook complexity, ignoring facts that don’t fit. The danger is that we are even more ignorant of our blindness when the narratives come with the gloss of science.

Karl and I pause to give his knee a rest.

“How do you reconcile this?” he asks. He doesn’t think David Reich’s analysis of the genetic material is wrong. “All I know is that the archaeological record doesn’t conform to the DNA, and the DNA is supporting a narrative that archaeology finds difficult to support.”

“And you draw the parallel in Jane’s case,” I say.

Karl doesn’t answer.

We start walking again, and when we get to the restaurant, I hold the door open for him.

“I’m not an invalid yet,” he says.

As always with Karl, we luxuriate in time. Three hours go by at lunch. His eyebrows look like tumbleweeds trying to roll toward his ears. We reminisce about other people on the Tepe Yahya digs. He shoots me a glare when I ask him about Christine Lesniak, the woman who disappeared. “Christine?” He pauses, then says he doesn’t think Christine was ever particularly interested in becoming an archaeologist. “She dropped out of school, and I don’t know what happened to her. I have no idea.” We don’t get into it.

He says he didn’t talk to Jim again after Jane died. Didn’t Jim go to Tepe Yahya with you a few more seasons? Oh yes oh yes, he says, and seamlessly changes the story to we never talked about Jane again. He insists that you couldn’t fail out of Harvard by failing your Generals. That Jane had only been scheduled to take her exams once.

I know that these statements are false, and I wonder if he’s told the story like this so many times that he doesn’t remember the way it really was. But then I realize this conclusion might speak more to the limitations of my own perspective: If I’m the one who’s rehearsed the details of Jane’s life with the regularity that obsession demands, is it his fault for not remembering?

Toward the end, we order espressos and as he holds the tiny cup, his signet ring on his pinkie catches my eye. I had wondered about it since that first class of his I sat in on.

“What’s the iconography on your family crest?”

“A coat of arms,” he says first, and then, “Dogs. Hunting dogs.”

“Why?”

“Hunting in Europe is a status aspect. And you display the horns of your—” He pauses, perhaps to weigh whether he wants to say the next word or to emphasize it. “—kill.”

One of the Habsburg emperors had decided he wanted a keeper of the hounds, and he chose a relative of Karl’s. Karl’s family crest has had a hunting dog on it ever since. The signet ring, I later find out, was his father’s.

“But we came to talk about Jane,” Karl says. He seems uncomfortable talking about his family history and taps on the table, searching for words. “It’s—I don’t—” He keeps stopping himself mid-sentence, until finally he says: “I’m not quite sure why I’ve been so lucky.”

I press him on what made him think of luck, and he dodges the question.

“Right place at the right time. Meeting the right person at the right time. Selecting the exact appropriate wife. God, we’ve been married fifty-eight years. It’s a long time. A long time.”

“What made you think of luck there?”

“No two have ever had a better time than I’ve…we’ve had a wonderful time. We surely did.”

“What made you think of luck?”

“Oh, luck. Luck that I got the education that I was able to get. Luck that I married the right person. Luck that I stayed out of jail my whole life. I always believed that luck comes to the well-prepared person, and I mean that only in the sense of scholarship. I worked hard to master—to pretend to master the field,” he corrects. “It sure as hell was worth it.”