Fiona Bennett certainly remembered. Everything about Susan Wright became increasingly clear to her, the more she tried to forget. And her special memory for dates made that day immediately leap to mind.

It was a Tuesday.

November 11, 1997, Tuesday. It didn’t rain. Susan Wright took advantage of her lunch break to participate in a venous drug trial; when she went to have her second blood sample drawn that afternoon, she felt nauseous, then vomited, and was immediately taken to the hospital. It took her two days to recover, and they said it was a drug allergy. After one more day of observation, Susan Wright returned to school on Thursday and resumed classes as normal. Incidents like this occasionally happened during drug trials and weren’t considered rare. However, judging from the content of the first letter, this was actually a deliberate poisoning.

Fiona Bennett herself had never participated in a drug trial, so she wasn’t clear on the exact procedures or which steps might have loopholes that could be exploited. All she could do was rely on Gabriel Adams to investigate and see if any clues could be found nine years later. Naturally, this was extremely difficult, but the key point in Gabriel Adams’s questioning was to confirm that the first letter was written and sent on November 11 or 12, 1997.

Another reference point appeared in the seventh letter. This letter mentioned the bottle of mineral water with a pinhole; it was from that day onward that Fiona Bennett became fully involved in the poisoning case. That day was November 26, 1997.

A third reference point was in the ninth letter. This letter mentioned Fiona Bennett’s ongoing investigation, which lasted only three days in total. On the evening of the third day, Fiona Bennett fell into the corpse pool. The letter said that Fiona Bennett had already spoken with several people, so it should have been written on the second day of the investigation—December 2. Or possibly the third day.

In the first two weeks, seven letters were exchanged, averaging one every two days. The eighth and ninth letters were longer, taking three to four days each. The tenth letter was likely written on the day Fiona Bennett had her accident. The eleventh letter, in a definite tone, mentioned Fiona Bennett’s “learning a lesson,” which meant that only after Fiona Bennett’s mental state had stabilized for some time, and she still showed no intention of pursuing the matter, could such a conclusion be drawn. So, it must have been at least three to five days after her hospitalization.

After probing each other through a dozen or so letters, the two murderers finally decided to meet. In the last letter, they agreed on a meeting place, thus ending their evil correspondence. Not long after the two murderers met, Susan Wright died. The meeting was set for “this Wednesday.” To allow time for the letter to be delivered, the safest time to mail it would have been Sunday or Monday. Judging by the previous back-and-forth timing of the letters, the Wednesday when the two murderers met was either December 17 or December 24—no earlier or later. Susan Wright died on the 27th.

Based on the previous frequency of correspondence, December 24 seemed more likely, but Gabriel Adams leaned toward the 17th.

“If it were the 24th, maybe the letter would have mentioned Christmas Eve,” Gabriel Adams said. “Of course, that’s not certain. The main thing is, from the previous letters, the main poisoner is the author of the second letter—let’s call them Perpetrator B. Their method was multiple small doses of poison, while Perpetrator A seemed to be B’s admirer. After the two met, they probably wouldn’t have changed this approach. And Susan Wright collapsed during anatomy class on December 26 and died on the 27th. If the two only met on the night of the 24th, it seems there wouldn’t have been enough time for them to coordinate. Of course, a sudden outbreak from accumulated toxicity can happen at any time, but I still think it’s more likely they met on the night of the 17th, and over the next nine days, they worked together to poison Susan Wright multiple times, leading to her poisoning on the 26th.”

“The 17th—that was the day I was discharged from the hospital.”

On the very night she was discharged, the two murderers met. This timing made Fiona Bennett feel as if there was a chilling, bone-deep logic to the workings of the world.

“On the nights of the 17th and 24th, was anyone with you?”

“On the 24th, Christmas Eve, Frank Bishop and I watched a movie, then he went home to look after his sick mother. As for everyone else, they were all out celebrating Christmas and didn’t return to the dorm until very late. Oh, I saw Susan Wright; she ran out from the pine grove, and she looked terrible. The meeting place in the last letter was in the pine grove—could it be she saw the two people who poisoned her? Is that why she was poisoned to death just two days later?”

Gabriel Adams shook his head. “It’s still the same old question: if she knew who the poisoners were, why didn’t she call the police? At the very least, she could have reported it to the school. So, what about the 17th?”

“I was discharged in the afternoon, went home for the night, and didn’t return to school until noon the next day.”

Gabriel Adams sighed. He had hoped to use the process of elimination to narrow down the suspects, but hadn’t managed to rule out a single one. Still, having established a rough timeline for the letters meant they now had reference points, which would be useful for future comparison.

“But on the night of the 17th, I talked with Frank Bishop on the phone for a long time. Definitely past nine o’clock, maybe even after nine-thirty,” Fiona Bennett said. “Of course, Susan Wright had already said it couldn’t be Frank Bishop. I’ve lived with him for so many years—he’s innocent.”

Gabriel Adams nodded, wanting to say something but swallowing his words.

“You think he’s a suspect?” Fiona Bennett asked, a little surprised.

“There are always people with bigger or smaller suspicions. Your husband is definitely the least suspicious. But from an investigative standpoint, I can’t say he’s completely ruled out. As for what Susan Wright said as the victim, it may not be correct, since we don’t know why she made that judgment. But the fact that you talked with him on the phone until late is a stronger point. Still, after so many years, there could be errors in memory. Or maybe my judgment is wrong, and the meeting was actually on the night of the 24th. I know you won’t like hearing this, but my advice is: until the investigation is clear, don’t trust any of your classmates.”

Fiona Bennett fell silent.

“Have you told your husband that you want to investigate Susan Wright’s cause of death?”

Fiona Bennett shook her head.

“That’s for the best. Let’s keep our contact one-on-one. It’s not that I suspect he’s the killer, but everyone has people they trust deeply. You trust him, and he surely has a few classmates he trusts especially. If the real killer finds out you’re investigating, you could be in danger.”

“I understand.”

Gabriel Adams looked at Fiona Bennett. To be honest, he was a bit worried, and even doubted whether reopening the investigation was wise. He had originally thought that uncovering the truth would help Fiona Bennett’s mental state. But as the whole matter slowly unfolded, it became a whirlpool, making it harder and harder to keep one’s footing. The psychological pressure Fiona Bennett was under now was clearly heavier than before.

Gabriel Adams checked his watch: 2:20 p.m. That morning, Fiona Bennett had called him, not saying much on the phone, only that she had a very important clue and they had to meet as soon as possible. He’d planned to be out for just an hour or so, but now… Gabriel Adams made two calls to arrange work matters, so he could stay out longer. He felt he needed to spend more time with Fiona Bennett—not so much to analyze the letters (in that regard, Fiona Bennett couldn’t help him; he would talk, she would listen), but because Fiona Bennett needed someone to talk to, to discuss things with, to have some psychological support. Otherwise, being alone at home, facing those fourteen letters, would be unbearable.

Next, Gabriel Adams began to analyze the handwriting.

“Look at the writing on these letters,” Gabriel Adams pointed out to Fiona Bennett. Both people’s handwriting was unattractive, each stroke stiff and awkward, with no structure at all. This showed they had both deliberately avoided using their usual handwriting habits.

“Perpetrator A’s writing is a bit better. Do you notice anything about B’s writing? The horizontal strokes always slant up on the left and down on the right, sometimes the finishing stroke is sloppy, and occasionally a line of writing drifts further and further down to the right. If the letter paper didn’t have horizontal lines, I bet this last feature would be even more obvious.”

“What does that mean?” Fiona Bennett asked.

“It’s classic left-handed, non-dominant handwriting. That is, the letter writer is normally right-handed, but deliberately used their left hand, resulting in these features. The trust between these two people was built up bit by bit. They knew very well what would happen if they were caught, so they were extremely cautious at first, avoiding any information that could reveal their identity. Since they were so careful, any identity clues they showed could be misleading. For example, Perpetrator B’s speech is simple and direct—maybe just because it’s hard to write with the left hand, so they kept it short on purpose. And the roughness they display doesn’t match the identity of a medical student. Do you have any classmates who normally speak that roughly?”

Fiona Bennett shook her head and said no.

“Exactly. Would someone who usually acts refined suddenly reveal their true nature in such dangerous correspondence? Of course not—they’re pretending. Faking handwriting, faking personality—so is it possible they’re faking gender too?”

“You mean, the one who writes roughly is actually a woman?”

“In terms of convenience for poisoning, it’s most likely both are women, and least likely both are men. One thing is certain: if you look for the letter writers among your classmates based on the personalities shown in the letters, you’ll be led astray.”

“Ah, I was still guessing which classmate matched the personalities in the letters one by one.”