The Small Room Inside Gray Thread

The final reverse verification began in the small room inside Gray Thread. Yeoreum took down every case chart taped to the wall and spread them across the table. She pushed Baek Sangho's name aside, and Jang's name, and Han Gyeongmin's name too. In the center, she left only actions and timestamps.

At nine in the morning, the outside reviewer arrived. He read the materials like a man who didn't believe Gray Thread's conclusion, and in fact, he didn't.

"There are a few links here that hold up even without Baek Sangho."

He wrote down three: a shared emergency key, a shared case, and a proxy payment. With a shared key, other workers could have accessed the stairwell too. With a shared case, it was unclear whose hands the fluorescent paint had come from. With a proxy payment, an account under Baek Sangho's name could have covered for someone else's actions.

Minu made a face, but Yeoreum copied the reviewer's paper exactly as it was.

"Let's set these three up as the strongest alternatives and see how far each one holds."

Seojin didn't pull the note with her ability's output from the file box. Leaving it out could weaken the chain, but the first condition of reverse verification was passing the same questions without the ability at all. She deleted that entire cell from the gray chart.

The first alternative was a shared emergency key. The facility company's entry log stated that multiple people could use the same key. But the time when the test count spiked the day before the incident overlapped exactly with Baek Sangho's solo work hours, and no one else had entered. The possibility of Gyeongmin's negligent oversight still remained, but Gyeongmin submitted call records showing he'd been in an outside meeting at that time. That didn't rule out the possibility that the records were false, but the emergency key alone couldn't transfer Baek Sangho's actions onto someone else.

The second alternative was the shared case. The case was company equipment, so many people had handled it, and the blue powder on the wheels could have come from any number of places. The lab reconfirmed the bonding order of the fresh paint and the old stairwell dust. The result stood: the fresh paint had been pressed down first, and the stairwell dust and the victim's blood had layered on top of it in sequence. The fact that the case was shared blurred ownership, but it couldn't erase the stratigraphy showing that real movement had happened after the test.

The third alternative was a proxy payment. Baek Sangho's account password could have been shared with several people, and the customer number on the blue triangle receipt might have been used in common across the editing service. So the reviewer said not to pin down ownership by payment alone. Minu moved the payment records off the center of the suspicion and out to the outer ring of links.

"Doesn't this weaken the case for pinning it on Baek Sangho?"

"It only looks weaker once you remove the overstated links. If what's left holds up independently, it actually gets stronger."

The reviewer counted them separately: the emergency key test log from the day before the incident, Baek Sangho's personal payment token, the failed remote reset, the blood stratigraphy on the case, and the USB access time. None of them explained the murder on its own. But each of the three alternatives failed to explain one link or another.

At eleven in the morning, Baek Sangho requested a face to face interview. He admitted to the illegal subcontracting and the video editing, but claimed Han Jaehee's death had been an accident.

"That woman pushed the case and went down the stairs herself. She might have collided with Han Gyeongmin."

Minu didn't raise his voice even hearing that. He first wrote down Baek Sangho's account exactly as given, self injury or collision, two alternatives. Then he brought out the physical evidence one sheet at a time.

The first was the layer where the fresh paint had been pressed. Baek Sangho said it could have come from a different case. Minu laid the wheel spacing from the crime scene side by side with the test photo of the same case. The second was the emergency key test. Baek Sangho called it routine inspection, but it didn't match the official work schedule. The third was the personal payment and the failed remote reset. Baek Sangho kept repeating that the account was shared.

"If it was a shared account, why did the reset attempt on that storage unit come from the account under your own name?"

"Someone must have used my account."

"Then how did that someone know the storage unit's number?"

Instead of answering, Baek Sangho drank some water. Minu moved on to the next piece of evidence: the USB's external hash and its last access time. Baek Sangho's device identifier could theoretically be duplicated, but the access time overlapped with other records from before and after the incident. He still insisted he'd lent out the device.

"Who did you lend it to?"

"I don't know."

"Then why did you try to reset the storage unit?"

"I didn't know the USB was in there."

Each of Baek Sangho's explanations was possible on its own, but they couldn't all hold true at the same time. He claimed to have lent out the device while also claiming not to know about the storage unit, and claimed not to know about the storage unit while also attempting a remote reset on it. It wasn't a confession, but the alternative timeline kept breaking apart.

Watching the scene from beyond the glass, Seojin opened her notebook. If she used her ability, she felt she could know instantly which of Baek Sangho's words were lies. But knowing instantly and proving it were different things. She wrote "ability not used" in her notebook, and beside it, the numbers of the independent evidence.

At half past two in the afternoon, a briefing was held for Dabin and Gyeongmin. It was a session to separate what would be disclosed before referral from what would not. Dabin asked first whether the informant's original statement would truly stay sealed. Gyeongmin asked whether his own subcontracting violation and the correction of his past misjudgment would be included in the referral materials.

Seojin didn't give the same answer to both questions. She showed Dabin the disclosure restriction chart and the review procedure, and showed Gyeongmin the correction statement and the responsibility chart, separately. It was so that the fact of catching the culprit wouldn't erase the different consequences each of them still faced.

Dabin revised the "call time correction" item on the restriction chart. She asked that instead of deleting the time she'd gotten wrong, both the original time she'd stated and the corrected time be left in together. Gyeongmin asked that the misjudgment record be disclosed, but requested that the reason Dabin had lied not be written down.

"If you hide the reason, people will invent another story of their own," Yeoreum said.

"That doesn't mean we should write down the child's name just to stop that story," Gyeongmin replied. "Please separate the part I'm responsible for from the part Dabin gets to choose."

Dabin didn't look at Gyeongmin even after hearing that. She signed only her own attachment sheet. Gyeongmin signed a separate responsibility sheet as well. Not writing the same conclusion on the same document was, this time, the way to protect both of their safety.

In the evening, the outside reviewer stripped the ability's output and speculative motives from the final chain. What remained was the test log from the day before the incident, the case's stratigraphy, the personal payment and the failed storage unit access, the USB's restricted metadata, and the collapse of Baek Sangho's alternative statements. The reviewer deleted the sentence "Baek Sangho knew of the entire conspiracy" and replaced it with "identified as the key party with access to the physical execution and the theft attempt."

Minu didn't like the phrasing, but he signed it. Jang's role was separated out as after the fact editing execution, and it was noted that evidence he'd known of the murder plan in advance was insufficient. The list of culprits had narrowed, but the scale of the wrongdoing hadn't been inflated.

In his final interview, Baek Sangho asked Minu a question.

"Does a person die just because 17 seconds are missing?"

Minu looked at the scene photo for a moment. "The person died on the stairs first," he said.

No one demanded a confession after that. The evidence chain was being completed not by confession, but at the place where every alternative explanation had collapsed. After the briefing ended, Dabin stopped in the hallway. Gyeongmin stood a few steps behind her, but he didn't approach first. Seojin watched the distance between the two of them and told neither one to move.

"I'll correct the time I changed," Dabin said. "But please don't write down why I changed it."

"If the reason is left out, the meaning of the correction might get blurred."

"Just until I can explain that meaning myself, all of it."

After a long moment, Gyeongmin said, "Please do that."

Dabin didn't thank him for it. Gyeongmin didn't keep apologizing either. Instead, the two of them each took their own separate attachment sheet. It was still far from something you could call a restored relationship, but at least what remained was a state where neither one decided the other's scope of disclosure for them.

Back at the office, Seojin checked the order of the evidence chart again. The test log from the day before the incident came first, and the case's stratigraphy came next. The personal payment and the failed remote reset had come from different sources even under the same account. The USB access time matched the device identifier, but actual file access hadn't been confirmed. That limitation had to stay exactly as it was for the report to hold up over time.

While reading the draft of the referral document, Yeoreum deleted the word "conspiracy." It had been confirmed that Jang was paid to do the editing, but there was no evidence he'd known of the plan before the harm occurred. Adding that one word would have made the document look stronger, but in a later review the entire chain could have shaken along with it.

Minu said, "You're being awfully careful, even though the victim is dead."

"We have to be more careful precisely because the victim is dead," Yeoreum answered. "If we use her case to pin down someone we're not even sure about, that's using the victim's name twice over."

Hearing that, Seojin set the long term questions aside on their own. The blue triangle lineage, the 17 second render prefix, the customer number that might overlap with the Yun Junho case. All of them were important connections, but she didn't put them into this referral's conclusion. Those connections needed to come back as falsifiable questions in the next case.

At nine at night, the outside reviewer sent his final opinion. There were five grounds identifying Baek Sangho, and each ground was listed with its independent source and its remaining conditions for rebuttal. "The possibility that someone else used the emergency key" hadn't been closed off entirely, but even in that case, someone would still have to explain the remote reset on Baek Sangho's account and the USB access time. The reviewer wrote that he hadn't found that explanation yet.

Seojin wrote her own name at the end of the document. She hadn't submitted the sense of the original word she'd gained through using her ability as evidence, and she didn't hide that fact either. Not listening wasn't a weakness in the investigation, it was the choice that let everything be reconfirmed through independent material.

The lights in Gray Thread went out one by one. On the hallway monitor, the storage number of the sealed USB still remained. Dabin read through the third party institution's confirmation letter once more, and Gyeongmin revised the correction statement one more time. Minu didn't change the order of the referral materials.

Seojin read the last line.

"Baek Sangho's physical execution, the USB theft attempt, and the outsourced editing order are referred as separate scopes of responsibility. Non-disclosure of the original statement is maintained as the victim's choice, and long term connections are registered as hypotheses."

That sentence didn't close the case completely. Instead, it drew a line between what was closed and what remained open. Seojin folded the gray chart and put it away in storage. Inside it were the sentences she'd discarded before ever reaching the answer, so that the answer would never be overstated.