"Not necessarily every test was done. There are so many types of heavy metals, and now it seems there are new instruments that can test for several heavy metals at once, right? Back then, it was probably still specific reagents for detecting a particular heavy metal. She could ask the hospital to test her urine two or three times, but if she asked for more, the hospital probably wouldn't agree. Would she really tell the hospital directly that she suspected she was being poisoned, so she needed repeated tests?"

Fiona Bennett thought of Susan Wright's attitude when she called the police that time and shook her head.

"So I just want to use a process of elimination. If I know what tests she had done, I can rule out those sources of poison, and then look at the remaining poisons to see which ones are relatively easy to obtain from the medical school." Gabriel Adams explained his preliminary investigative approach to Fiona Bennett.

"This is one lead. Another is handwriting. Although both people disguised their handwriting in the letters, for a handwriting expert, there are still traces to follow. But the premise is to get enough everyday handwriting samples for comparison. As for that, I'll try to think of a way, but maybe it would be easier for you? You should try to think of a way too."

"Okay," said Fiona Bennett. "They write medical records and prescriptions every day, so there should be a way to get some."

Summing up the week's findings didn't take Gabriel Adams much time. He saw that Fiona Bennett looked more haggard than a week ago, so he didn't want to go into too much detail. He thought Fiona Bennett might not be able to help him much with the investigation, and talking too much would only trouble her. It was enough just to make the progress clear. He actually wanted to chat with Fiona Bennett about other things, just some casual small talk, but felt it wasn't appropriate or convenient. They were already strangers, so it was best to stick to the original purpose and not complicate things further. He thought, if not for the lingering effects of what happened back then, Fiona Bennett and Frank Bishop's life would be happy. Now, he was trying to remove the root of the problem, and in the future, if they could occasionally meet and chat for a bit, that would already be very good. In this way, Fiona Bennett would be back in his life, but he would never be in Fiona Bennett's life—not in the past, and even less so in the future.

When Gabriel Adams fell silent, slowly turning his teacup, Fiona Bennett also quietly gazed at the broad leaves of the peace lily by the table. There seemed to be a tacit understanding between them. The calm gradually became awkward, then turned subtle, and finally returned to calm. As evening approached, during this time, the clouds parted, the sun shone on the bamboo leaves for a while, and then disappeared again. Just as they had finished the last of the tea in the pot, they parted ways.

After returning home, Fiona Bennett considered how to obtain her classmates' handwriting. In theory, they wrote a lot of prescriptions and medical records every day, but actually getting samples was difficult. She was no longer a doctor and only occasionally went to the hospital, not often. She couldn't ask Frank Bishop for help either; when he burned those letters, his wife didn't stop him, so he naturally assumed she didn't intend to investigate further. Fiona Bennett felt this was for the best—until there were results, it was better not to break the peace at home.

Up until the next meeting, Fiona Bennett still hadn't come up with a good solution. She also realized that prescriptions or medical records might not be good choices, because the writing on them was especially sloppy for the sake of speed, and didn't reflect the doctors' normal handwriting—so they weren't good samples. So what would be good samples? Every doctor had to write an annual work report, and the handwriting on those was the best example of their everyday writing. Fiona Bennett thought of this because she heard Frank Bishop mention that the hospital office was moving the archives to the new hospital in Pudong, so she started thinking about what handwritten documents by doctors might be in the archives, and the work reports naturally came to mind. The doctors' reports from previous years should all be in the archives. But even though she thought of it, Fiona Bennett wasn't a hospital staff member, so she couldn't just hang around and steal reports during the move. So when they met, Fiona Bennett only managed to find a few New Year's cards from classmates to give to Gabriel Adams. Gabriel Adams accepted them, but said they weren't very useful—there were too few words on the cards for meaningful comparison. Gabriel Adams asked, "You must have some of Frank Bishop's handwriting, right?" Fiona Bennett replied, "Why, do you still suspect him?" Gabriel Adams said, "You don't have anything else right now, so let's completely rule out your husband. From a criminal investigation perspective, even the smallest possibility is still a possibility—there's no harm in ruling it out. Don't be upset." Fiona Bennett wasn't upset and said, "Okay, I'll bring it next time."

Gabriel Adams thought the idea of using work reports was great. If he could get all the reports from previous years, it might just be enough for basic analysis. As for how to get them, Gabriel Adams said, "Don't worry, leave it to me." Fiona Bennett couldn't imagine what method Gabriel Adams might have, and thought he was amazing—was he going to sneak into the archives at night dressed in black like in the movies? As it turned out, two weeks later, Gabriel Adams said he had gotten the reports. It turned out that before the archives were moved, there was a big clean-out, and all the useless documents were packed up and sold to the recycling station. The work reports were obviously among them. They were supposed to be shredded, but in practice, no one enforced that strictly. Once the documents reached the recycling station, it was very easy for the police to go and pick out some files. Florence Bennett thought, he must have guessed this would happen, which is why he agreed so calmly.

The comparison of Frank Bishop's handwriting was completed first, and no obvious similarities were found. Although Fiona Bennett already knew he couldn't be the one, this still put her mind at ease. As for the other classmates, it would take several more weeks—there was too much work, and as Gabriel Adams put it, this time he owed that teacher a big favor.

The investigation showed that back then, Susan Wright had a lot of tests done at the hospital. For heavy metals, lead and arsenic were ruled out; for light metals, aluminum was ruled out. In addition, she was tested for blood parasites. All of these were non-routine tests, and having so many done during a short hospital stay was enough to make the impatient doctors and nurses give her dirty looks, thinking she was a hypochondriac. But with so many types of heavy metals, only a few were ruled out—there were still too many possibilities. Gabriel Adams gradually realized that, nine years later, if the ashes couldn't be tested, it would be impossible to identify the poison based on symptoms alone.

Gabriel Adams also did something that Fiona Bennett thought was quite ingenious. Because the letters mentioned several novels—"Dream of the Red Chamber," "The Smiling, Proud Wanderer," "The Deer and the Cauldron"—he designed a survey and hired a few college students to conduct a reading habits survey among young professionals. Of course, in reality, the survey was only done among the young doctors at the hospital. The questionnaire listed many book titles, and respondents were to check off the ones they had read. Among the classics was "Dream of the Red Chamber," and among the popular novels were "The Smiling, Proud Wanderer" and "The Deer and the Cauldron." The operation itself was a great success; all the target individuals participated. But the results were disappointing: all the male classmates had read the two martial arts novels, among the female classmates, Lily Carter had read them, and Crystal Nelson had only read "The Smiling, Proud Wanderer." All the female classmates had read "Dream of the Red Chamber," and among the male classmates, Quincy Hayes had read it. These novels were just too popular to help narrow down the suspect.

Fiona Bennett increasingly felt that Gabriel Adams was very resourceful, but Gabriel Adams himself didn't think so. In fact, compared to his time in the criminal investigation team, he felt extremely constrained. Handwriting, medical records, reading background—these were all indirect evidence, and some couldn't even be considered evidence. So much time had passed that most effective evidence had already disappeared, and he couldn't directly dig up what little remained, because he had no official status. Household registration police and criminal police are two different things, and whether a case is officially filed or not makes an even bigger difference. Even after using all his connections and trying every possible way, a week's progress couldn't compare to an hour of a real criminal investigator's work. If the case were officially filed and he were the investigating officer, things like medical records and handwriting samples would only take a phone call or a few words in person, and more time could be spent interviewing people involved in the case. Evidence may be buried by time, but people are still around, and skillful questioning can quickly narrow down the direction, reduce the scope, and dig up clues buried in the past. But now, every time he questioned someone involved, he had to make up a reason, and because of this fabricated reason, his questions could never be as direct or in-depth as those of a real investigator. He used to think those semi-underground private detectives were all useless, but now he knew this job was indeed not easy.

Gabriel Adams felt like a vulture, always circling for a long time before swooping down, but never getting enough to eat. Things were progressing with difficulty. He found Leonard Cooper, the senior who had a crush on Fiona Bennett back then and once helped her test mineral water for toxins. After graduation, Leonard Cooper stayed on as a teacher. This time, Gabriel Adams didn't come up with any special reason—he just said he was a friend of Fiona Bennett's and wanted to learn more about the testing back then. He deliberately wore his police uniform to seem mysterious. After graduation, Fiona Bennett hadn't kept in touch with Leonard Cooper, but he still remembered the incident. Seeing Gabriel Adams in uniform made him a bit nervous, because back then Fiona Bennett had said the reason was that an elder at home suspected there was poison in the water, and now, nine years later, a police officer was asking about it—was something wrong? Gabriel Adams said, "It's nothing, don't worry. We're just having a casual chat today. Just say whatever comes to mind. This has nothing to do with you; I just want to understand the situation." This sounded very intimidating, and sure enough, although Leonard Cooper looked like he wanted to escape, he still cooperated and answered the questions.