“Just listen, though,” he says. “Will you listen? And then I’ll go. Sophia hated Lance. I mean, she couldn’t stand him, no matter how much I liked him. She thought he was pompous and lazy and, more than anything else, a sexist. She hated that he used to have those parties and let underage kids drink and get high. It’s not that she was a prude. It’s just that she thought an authority figure like a professor shouldn’t be doing that kind of stuff, especially now. She went to one of his parties one time. Once. That was the night with Madeline, and, okay, I’m not proud of how I acted. Sophia had gone home early because she thought Lance was so gross.”

“You should have gone with her. She had good sense.”

“I can’t relitigate the past,” Zach says. “But I’m telling you she hated Lance. And she really turned against him even harder right before she died. She used to just roll her eyes about him, but all of a sudden, she acted like he was the lowest of the low. She told me she didn’t want me even agreeing to play golf with him or talking to him. She said I shouldn’t have anything to do with him.”

“Why the change?” I ask.

“I don’t know. She didn’t say. But on the news they’re saying Lance was sexually harassing Madeline. And maybe Madeline told Sophia. If that’s true, that might be why she took such a harsher view of Lance. He went from being a loser to a harasser. And Sophia really hated anyone who abused their authority that way. She really got righteously indignant when she heard about stuff like that.”

So far, everything he says tracks. It makes sense.

“Okay,” I say, “so Sophia found out about Lance harassing Madeline and confronted him about it. She wanted to protect her friend, her mentee, I guess. She went to Lance, telling him to knock it off, and he killed her to keep her quiet. If it came out that Lance was harassing a student, he probably would have lost his job, even if it happened over two years ago. And it would have been embarrassing for him. He had reason to protect himself.”

But Zach is shaking his head. He looks certain.