Shirley tracked him with her eyes, her expression malevolent. After he shut his door, she heaved herself to her feet and led me silently to the front of the house.

I handed her one of my cards, urging her to phone me if there was something else she could tell me about where Sonia might have last seen Matt Chastain. The graveyard Sonia was obsessed with could easily be a metaphor for her own buried hopes; perhaps Matt had talked to her there, kissed her, done something that made her feel that a particular spot was sacred.

“It was over thirty years ago, so I don’t remember.” Shirley pushed open the outer door. “Anyway, everyone was confused. What was real, what was imaginary, how could I know? I wasn’t there.”

“What happened?” I said. “What went so wrong with the experiment that Matt Chastain felt he had to run away?”

“Nate doesn’t confide in me.”

I would have believed her more readily if she hadn’t swallowed a sly smile before answering.

“I don’t know anything about this kind of work, but something going wrong with an experiment—was there an explosion? Were people hurt? Or did something your husband worked on make people sick?”

She looked startled, even alarmed. “I don’t know, and anyway, I just told you, it was a long time ago.”

“But your daughter must have seen something, if it terrified her so much that she had to cover the memory with the protective story that Chastain had died or been killed.”

“My daughter,” and she again invested a shocking amount of venom in the two syllables, “was sneaking out of the house and trailing around after poor Matt. Dr. Chesnitz says the most likely scenario is that she flung herself at Matt, who rejected her. She was fourteen, overweight, not the kind of girl anyone would respond to, let alone a young man in his twenties. Chesnitz says that in Sonia’s mind Matt had to be punished by death. Thinking he was murdered helps her blot out the memory of the rejection and turn him into an idealized figure who was in love with her.”

“It sounds like a convenient theory,” I said.

“What’s that supposed to mean?” She thrust her head forward in her signature turkey move.

“Keeps anyone from asking too many questions about what really happened, or where, or how.”

She started to bristle, but I interrupted to ask if her sons kept in touch with Sonia.

Her expression darkened. “I wouldn’t know. They couldn’t take Nate, his bullying and his moods. Stuart went to school at Bowdoin, out in Maine, never came home after his sophomore year, and Larry, he went to college in Oregon and stayed out on the West Coast. If they talk to Sonia, that’s something you’d have to ask them.”