“The school year is nine months, which is about thirty-six weeks,” Brian said. “That would be, let’s see, seventy-two thousand a year—”
“And not just this year,” Gregor said. “I think we’ll find, when we look into it, that this has been going on for close to a decade. Students come and go, after all. And if your perpetrator was careful, he’d come and go, too. He wouldn’t always do the same thing at the same time in the same way. Heor she, I should say. The British police give their murderer a name when they start their investigations, or they do if you can believe P. D. James. She’s the only detective novelist I read anymore. Maybe because it’s the British police forces she’s dealing with, and I don’t know enough about those to know when she’s wrong. With the American mysteries, I’m always fighting with the writer about procedure.”
“So this has been going on for years,” Brian said. “We could pull the records and demonstrate that?”
“I don’t know,” Gregor said. “It won’t look like anything different than ordinary student withdrawals. Our perpetrator must be intelligent enough to make the filching look like ordinary transactions. If not, he or she would have been caught years ago. I wouldn’t bet on the records by themselves; I’d bet on Mark DeAvecca.”
Brian raised his eyebrows. “What, Mark DeAvecca has some secret knowledge about the theft as well as about the death of Michael Feyre? I mean, okay, Gregor. He’s a bright kid when nobody’s poisoning him. I had him wrong. I apologize. But you’re turning him into a regular James Bond.”
“I’ll bet he’d like that,” Gregor said. “But no, it’s not that he’s a James Bond. It’s not what he knows about the perpetrator or about the death of Michael Feyre. It’s what he knows about himself.”
“And that’s supposed to mean what?”
“I’ve been thinking about it. The symptoms increased in severity after Mark came back to school after Christmas vacation, but they existed before then. They were just milder. Both Liz and Jimmy have said that Mark was being very peculiar when he came home for Christmas break. Now, that could just be the caffeine. He was drinking so much it could account for a whole lot of peculiarity. I wish they had videotapes of the way he was when he came home. Because the possibility exists that he was being poisoned long before Christmas, going back well into the fall.”
“But look at him now,” Brian protested. “He’s been away from the poison for a day and a half, and he’s a completely different person. Shouldn’t that have happened over Christmas break? If he was being poisoned up here, and he went home, then after a couple of days he should have started to feel much better.”
“Maybe he was still being poisoned when he went home.”
“His mother was poisoning him, too? What?”
Gregor brushed this away. “Edith Braxner is dead. She’s dead because she ingested cyanide. Cyanide works very quickly, within seconds, within minutes at the most. That means she had to have ingested the cyanide in the catwalk nook only moments before we found her. With me so far?”
“Of course.”
“She was up on that catwalk alone. I know that because I was standing in the main reading room right near the circular staircase that is the only way on or off it. How did she get the cyanide?”
“Marta Coelho was right there,” Brian said. “She could have given it to her.”
“Oh, I agree,” Gregor said. “Marta Coelho definitely could have given it to Edith, but even if she did, she must have given it in some form that would delay the ingestion. The perpetrator did not want to be around when Edith died. So Edith must have been given something, brownies or doughnuts or candy or something, to eat later. Right?”
“We’ve been over this before,” Brian said.
“Apply it to Mark,” Gregor said. “Think about him taking something home over the vacation, a gift somebody gave him, cookies laced with arsenic. Something.”
“It would have been risky as hell,” Brian said. “He could have had a pig-out and gotten himself killed. He could have given the damned things to somebody else and killed them.”
“Maybe there was something Mark and only Mark would eat, and that he’d only eat one of a day. Can’t you think of something like that?”
“No,” Brian said.
“I can,” Gregor said. “Prescription multivitamins.”
“What? Who gets prescription multivitamins?”
“Lots of people do,” Gregor said, “especially rich and relatively rich people who fret about their health and their children’s health. And no, don’t ask. Mark was taking prescription multivitamins. In capsules. He took his last one on the day I showed up here. He took it with water in my room at the inn.”