The Ordinary Words That Vanished

The four digits under the blue triangle were not an order number.

The person in charge of the payment processor's viewing room showed the last four digits of the customer number and blacked out the transaction name. Seojin didn't look at the blacked out field. The range Han Yeoreum had requested was the device fingerprint before and after the time of the incident, the approval time, whether it had been canceled, and part of the customer number.

"Can you confirm a match without opening the transaction contents?" Yeoreum asked.

"Yes. If the device fingerprint and approval time both match, the likelihood goes up. Though the customer number could have been reused."

Seojin checked the fold direction of the original receipt again. On the receipt: 22:14:08, the last four digits of a customer number, and the blue triangle. The remote editing session had been approved at 22:14:31. The device fingerprint was the same.

"There's a 31 second gap."

"The job could have been scheduled after payment," Minwoo said.

"Or the clocks on the two records could be different."

The person in charge produced the correction value between the server network time and the payment terminal's clock. The difference was 28 seconds. After correction, the receipt payment landed at 22:14:36. A 5 second gap from the remote session approval.

Seojin didn't circle that number in bold. Instead she made a table of four conditions.

Customer number match. Device fingerprint match. 5 second approval interval after time correction. No cancellation.

All four boxes matched.

"Can we say now that it was one transaction?" Minwoo asked.

"It's likely these are two records from the same device, continuous. That the payer was the actual operator is separate evidence."

Yeoreum spoke to the person in charge.

"When you prepare this data for court submission, we'll also need confirmation that no other customer's transaction data got mixed in."

"That's possible. I'll output the metadata separately."

Without looking at the original transaction contents, Seojin confirmed that an outside editing service had been requested for payment. The blue triangle stopped being decoration and became a transaction mark carrying a time, a device, and a price.

The merchant name on the payment terminal was abbreviated as "Blue Records Management."

Han Yeoreum closed the screen.

"We're not disclosing this name today."

"Why?" Minwoo asked.

"A payment service isn't the whole organization behind the case. If we disclose it now, the company could pull its equipment and accounts."

Seojin agreed, but she didn't want to hide the fact that she'd seen the name.

"Put it in the minutes. The abbreviated name Blue Records Management has been confirmed, but public disclosure is on hold."

Yeoreum copied down her sentence exactly.

At 5 p.m., in the server forensics room, they checked the remaining cache fragments. Part of the original file had already been overwritten. What they recovered was only the file allocation table and the render temp file name.

Seojin compared keyframe intervals in the submitted file. A new keyframe began right around the 17 second mark, and the temp file name carried the prefix "R17."

"Is this prefix a mark from an external renderer?" Minwoo asked.

"It could be a mark, but it doesn't confirm the company. A temp file name can be changed by the user."

Dohyun turned over the cache fragment.

"The file allocation table preserves the order in which the original index was deleted. Even if we can't recover the video content, we can confirm the act itself: a 17 second segment was made into a new file, and then the original index was erased."

For the first time, Seojin stared at the screen for a long while. Her brother's case had had a gap of the same length, and the same prefix had been left on a photograph.

She took an old photo out of her brother's case envelope. On it, the external renderer's temp file prefix was faintly stamped.

Minwoo asked.

"Why have you been holding onto that?"

"It's analysis material from my brother's case."

"Can you connect it to this case?"

Seojin set the photo beside the receipt. The blue triangle and the prefix seemed to point in the same direction, but that still wasn't evidence they were the same organization.

"It's a comparison item. I'll put it on the evidence board, but not in the conclusion column."

Minwoo nodded.

At 7 p.m., in the gray room lounge, the team laid out the partial answer to the first case. It was likely Han Jaehee had moved by way of the stairs, and it was now possible someone had recovered the USB. Baek Sangho had hidden the ledger and the USB, and had stated that he left after closing the door without checking on anyone. But the 17 second edit was connected to an outside service.

Minwoo said.

"We're splitting Baek Sangho off as a candidate physical actor, and Blue Records Management as a candidate editing service."

"Candidates," Seojin added.

"Understood. Candidates."

Yeoreum called Dabin in and explained the partial answer. Whether the USB had actually been taken hadn't been confirmed, but she told her first that her sister had had the USB and had apparently tried to pass it to someone, and that the timeline connected to Han Gyeongmin's misjudgment.

Dabin closed her eyes for a moment.

"You still don't know the whole reason my sister died?"

"No."

"Even so, can you find the USB?"

"We'll keep building independent evidence toward that, without disclosing the name of the person being protected, or the original statement."

Instead of answering, Dabin took back Han Jaehee's cable envelope. Rather than leaving every item with the investigation team, she chose to keep, herself, whatever she didn't want disclosed.

Seojin didn't log that as obstruction. It was a victim, having heard a partial answer, deciding for herself the scope of what to disclose about her own belongings.

Minwoo wrote two tracks in the minutes. First, the physical chain of the USB theft and the body's movement. Second, the payment and access chain of the 17 second edit and the outside service. The two tracks could intersect, but they weren't to be merged into a single confession.

At that moment the storage warehouse alarm went off. The notification said Baek Sangho had tried to replace the seal on a case in the warehouse.

Seojin laid the prefix from her brother's case photo next to the blue receipt. She didn't draw a line between them.

The first case wasn't over. Only one convenient explanation, that a single person had done everything, had been closed off.

On the way to the storage warehouse, Minwoo asked Seojin.

"Why did you bring out your brother's case photo now?"

"The same prefix showed up in this case too."

"Then you should compare them right away."

"Comparing and connecting aren't the same thing."

"That must be harder for you."

Seojin didn't answer. If she put her brother's innocence ahead of paying out the partial answer owed to this case's victim, Han Jaehee's case could turn into a certificate for her own family.

Yeoreum spoke from the back seat.

"Seojin, let's set the terms for disclosing this material to the team now."

"My brother's case material?"

"Yes. The scope that doesn't connect to the victim's original statement, the scope that directly compares against this case's editing traces, and the condition that we keep a written record of who accessed it."

Seojin set the photo down on her lap.

"I was planning to keep it to myself."

"I understand that feeling. But if you keep it to yourself, no one can stop you if you're wrong."

Yeoreum said "I understand," but she didn't attach absolution to those words. Seojin didn't take the photo out of the envelope. She only shared the photo number and the location of the record in the original case file.

Minwoo spoke with his hands on the wheel.

"We're not using your brother's case as the conclusion to this one."

"I know."

"And we're not using this case's original statement as compensation for your brother's case either."

Hearing that, Seojin resealed the photo.

The storage warehouse alarm meant the external seal number on the case had changed. Baek Sangho hadn't said he'd opened the case, and in fact the internal seal was untouched. He claimed the outer label had been damaged and he was trying to replace it with a new seal.

Minwoo didn't accept the claim right away.

"Why replace it now?"

"The label got wet."

"Why didn't you photograph the wet label first?"

"I replaced it according to company procedure."

Yeoreum demanded a copy of the procedure. Baek Sangho produced it, but the procedure included a clause requiring on site photos before replacing an outer label.

Baek Sangho took off his gloves.

"I skipped the order of steps."

"That fact goes in the record too," Minwoo said.

"I didn't touch the inside of the case."

Seojin photographed the outer seal number, the state of the inner seal, and the time of replacement, each separately. Whether the case held evidence, and whether today's replacement process had created a new loss, were two different questions.

The warehouse manager found a small scrap of paper on the floor beside the case. Part of a blue triangle was stamped on it, but it wasn't a receipt. It was an equipment checkout sticker. The mark had the same shape, but there was no customer number.

Minwoo said.

"So there are more items carrying the same mark."

"That's why one receipt couldn't confirm an organization," Seojin answered.

She moved the mark from the center of the evidence board to the side. Only the receipt with the customer number, device fingerprint, approval time, and cancellation status stayed in the transaction column. The sticker was separated into an operations trace column.

The move was small, but it changed the explanation. The blue triangle might not be an organization's signature. It could be a management mark used across multiple devices and transactions. Within it, the numbers and times pointing to the same device were the real link.

Dabin took Han Jaehee's cable envelope and said.

"I still won't say who my sister was trying to give this to."

"That's fine," Yeoreum said.

"But I won't hide the fact that the USB is missing."

Dabin wrote that sentence into the confirmation form herself. She sealed the name of the person being protected, but disclosed the state of the item the case needed.

At that moment, Seojin wrote down the smallest settlement of the first case. Knowing the truth and having the right to tell everyone weren't the same problem. Still, a person who had decided not to speak needed to be able to decide for herself what she would say.

On the way back to the gray room, the team split the next day's work into two. Minwoo took Baek Sangho's physical access, Yeoreum took separate preservation of the payment service, Dohyun took the format of the render temp files and Junho's case photos, and Seojin took the time discrepancy between the two cases.

No one put the name Blue Records Management into the public briefing. Instead, they filed away the confirmed transaction and the still unconfirmed role under that name.

Seojin wrote down the number of her brother's photo without unfolding the creased corner of the envelope. The final sentence of this case wasn't going to be her brother's innocence.

There had been a transaction ordering seventeen seconds from someone, and that transaction was separate from any one person's actions. Next, they needed to confirm who had actually received that order.