The Original Statement

Baek Sangho said he didn't know the server password. That part was true.

The remote account belonged to headquarters. Field technicians only had authority to swap equipment and check status. The problem was why he hadn't needed to open the server in the first place.

Minwoo went over Baek Sangho's statement again beside the field vehicle.

"The night visit was a safety inspection. I never accessed the server."

"Then why did you go looking for the ledger?"

Baek Sangho looked at the wrench handle in his hand.

"What ledger?"

"The illegal subcontracting ledger."

"That has nothing to do with the server."

"Answer the question."

"It's shared company equipment. I have a duty to keep it secure."

Minwoo set Seojin's timeline on the table. 4:58, emergency key not returned. 5:29, terminal login. 5:32, stairwell sensor. 5:35, server clock correction.

"What time did you find the ledger?"

"I never found any ledger like that."

"Then why did you agree to seal the cargo bed of your vehicle?"

Baek Sangho's eyes went to the cargo bed. He hadn't consented to a full vehicle search, but he had agreed to have the server case moved to a warehouse and sealed. It looked like the behavior of someone protecting an object that might connect to the murder, but there was another explanation too.

"Can we open the case and look inside?"

"No, it's company equipment."

"Then why did you agree to an exterior inspection?"

"To prove it doesn't need to be cleaned."

Minwoo wrote that sentence down. Baek Sangho denied having server deletion privileges, but he was sensitive about the condition of the equipment he'd taken.

Seojin photographed the case's wheels. Fluorescent colored powder clung to the rubber of one wheel. It looked like the same color as the paint on the eighth floor stairwell, but a visual comparison alone couldn't establish that they were identical.

"Can we say this means it went to the stairwell?" Minwoo asked.

"No."

"Then what can we say?"

"That the case came into contact with a fluorescent substance. We don't know the location or time of that contact yet."

Baek Sangho gave a short laugh.

"Machines don't lie."

"Machines don't explain either," Seojin said. "People are the ones who attach explanations."

The laugh drained from Baek Sangho's face.

He didn't hand over the whole vehicle. Instead he agreed to have the case moved to a third party warehouse and sealed. The people accompanying it were a supervisor designated by the facilities company Baek Sangho named, and Dohyun from the gray thread team. Minwoo wanted to attach a tracking device, but Yeoreum checked the scope of consent first and placed it only on the exterior of the case.

"We won't look at what's inside the case," Yeoreum said. "We're only confirming the transport route and the state of the seal."

"So you wouldn't know if the inside got switched?" Baek Sangho asked.

"That's why we file a separate request for the conditions under which we can look inside."

"That takes time."

"It's the time it takes to decide what we're willing to give up."

At 6:20 that evening, inside the moving vehicle, Seojin looked at the word "stairwell" again. At first it had been paired with the verb "flee." Now it was paired with the case's wheels, the scratch on the threshold, the impression mark on the server rack.

She drew a line through "stairwell = flight" in her notebook.

Minwoo asked from the driver's seat.

"Are you erasing that?"

"No. I'm leaving a record that I interpreted it that way."

"Then what do you write next to it?"

Seojin thought for a moment.

"Transport?"

She added a question mark.

As the vehicle turned down the underground ramp, the left wheel of the case caught on the threshold once. Seojin heard the sound, but she didn't reconstruct yesterday's scene from sound alone. She'd need to compare the height of the scratch on the door closer with the width of the case's wheels the next day.

Then a call came in over Minwoo's radio. Part of the subcontracting ledger found in a waste storage bin in the management office had been preserved along with the server records.

"Looks like it's true that Baek Sangho went looking for the ledger."

"We need to separate the fact that he found the ledger from the fact that he met Han Jaehee," Seojin said.

Minwoo didn't answer. He stopped the vehicle. He didn't let Baek Sangho check the ledger himself. He only notified him that it existed and had been preserved.

Baek Sangho spoke in front of the warehouse.

"If that ledger comes out, I'm fired."

"That could happen," Minwoo said.

"I have a family."

"That circumstance doesn't give you the right to destroy the ledger."

"You people look at a person's circumstances like they're just numbers."

Seojin answered.

"No. We're trying not to put a person's circumstances and their responsibility in the same column."

Baek Sangho glared at her. In the moment while he was about to say something, the seal sensor inside the warehouse went off.

The case itself hadn't moved. But a record showed that a small door at the back of the warehouse had opened and closed. Who had opened it would have to be confirmed with the security company's access card logs.

Baek Sangho tried to run toward it first, but Minwoo blocked his arm.

"If you go in now, you add another point of contact."

"Someone could be taking the ledger."

"That's exactly why we're preserving the front of that door."

Baek Sangho stopped. He hadn't looked at the ledger before the case. He hadn't looked at the case before the door at the back of the warehouse.

That behavior was suspicious. But suspicion was different from physical access rights.

Seojin photographed the door handle. Fresh oil had gotten onto it, and on the floor there were dirt marks of a different width than the case's wheels. It was possible that two people had used the same door.

Dohyun measured the width of the marks.

"The case wheels are eighteen centimeters. This is seven."

"Could it be a shoe?"

"It's possible. We can't confirm it's a shoe sole."

Minwoo asked Baek Sangho.

"Did you know about the back door?"

"It's the door the warehouse manager uses."

"Who used it today?"

"I don't know."

This time Baek Sangho's answer came too fast. Seojin didn't treat that speed as evidence of a lie. She just changed the order of the next question.

"Have you ever seen a USB drive, not the ledger?"

Baek Sangho's hand slipped off the wrench.

"I've never seen anything like a USB."

Minwoo looked up. No one had mentioned a USB drive.

Seojin wrote one sentence in her notebook.

'Denied an object no one asked about.'

That sentence wasn't evidence of the crime. But the fact that the server password wasn't the only thing Baek Sangho was hiding showed itself, for the first time, not in his words but in his reaction.

The door at the back of the warehouse was sealed. The case stayed where it was. The murder and the illegal subcontracting were separated within the suspicion of one man.

Seojin moved the case wheel width and the stairwell threshold height onto the same table. A field reconstruction would be needed the next day.

She drew one more small arrow next to "Transport?"

The possibility that the equipment had passed through the stairwell.

Outside the warehouse, Minwoo took Baek Sangho's statement again. This time he asked one question at a time.

"Why you took the key at 4:58."

"Server inspection."

"Why the terminal logged in at 5:29."

"To check the equipment's condition."

"Why you went looking for the subcontracting ledger."

This time Baek Sangho didn't answer right away.

"That ledger shouldn't have existed at the company."

"Why not?"

"There's a record of someone being sent to the site who wasn't in the contract."

"Who sent them?"

"Headquarters gave the order."

"What's the name of the person who gave the order?"

"I don't know."

Minwoo didn't look at Han Gyeongmin. Confirming whether Baek Sangho was telling the truth would require the headquarters' remote order logs. But the fact that Baek Sangho had tried to get rid of the ledger already amounted to a breach of contract and an attempt to destroy evidence.

"Do you admit you came to find the ledger?"

"Yes."

"Did you meet Han Jaehee?"

"No."

"Did you know she was on the stairs?"

Baek Sangho's gaze went to the warehouse door. A seal number was still fixed to it.

"I saw that someone was there."

Minwoo leaned forward.

"Who?"

"I didn't see a face. There was a sound from below the stairs, and I went in to find the ledger."

Seojin watched his actions more than the sentences of his statement. Baek Sangho took off his gloves not while denying the murder, but while talking about the person below the stairs. The motion of wiping the oil on his palms onto his pants repeated three times.

"Why didn't you say this from the start?" Minwoo asked.

"I didn't know who that person was, and if I said I'd been there, the ledger would come out too."

"Did you leave a person unattended to protect the ledger?"

Baek Sangho didn't raise his head.

"I closed the door."

"On whom?"

"I don't know."

Seojin gestured to Minwoo.

"Ask him about the time he closed the door first."

Minwoo changed the question.

"What time did you close the door?"

Baek Sangho seemed to be recalling the time stamp from his laptop.

"Around 5:33."

"Exactly?"

"5:33:41."

He answered with too much precision. He had memorized the time of his own action.

Dohyun checked the server log right away. At 5:33:41, no remote session had been open. Instead, the emergency stairwell sensor's closing event had ended at 5:32:31. The time Baek Sangho claimed to have closed the door differed from the sensor record by one minute and ten seconds.

"The sensor time and the terminal time are different," Baek Sangho said.

"So we'll look at both timelines together," Dohyun answered.

"Did you meet Han Jaehee?"

"No."

"Did you tell anyone she was on the stairs?"

"No."

"Then why did you deny the USB first?"

Baek Sangho's lips tightened.

Minwoo seemed to notice that choice and looked at Seojin. He turned the questions back to the timeline.

Baek Sangho finally spoke.

"There was a USB. I don't know if it belonged to Han Jaehee or someone else. I tried to take it along with the ledger."

"Why didn't you tell the police?"

"If the ledger comes out, my name comes out with it."

"So you closed the door and left?"

Baek Sangho nodded. That choice was different from a plan to hide a murder, but it was still neglect: knowing a person might still be on the stairs, and choosing to protect his own breach of contract instead.

After the statement was finished, Minwoo slid the signature line toward Baek Sangho.

"Your statement isn't a confirmation that you're innocent of murder."

"I know."

"We're recording the fact that you tried to destroy the ledger and the fact that you left a person unattended as separate matters."

Baek Sangho took off his gloves and signed. Fluorescent powder on the back of his hand rubbed off onto the edge of the paper.

Seojin didn't collect that powder. Whether it matched the substance from the stairwell the day before would need separate verification.

That night, the work of aligning the timeline of the warehouse's seal sensor with the stairwell door closer began. "Stairwell" no longer meant only flight. It was a place where someone had closed a door, moved equipment, and said nothing about the person they had seen.

Seojin didn't erase the question mark in her notebook. She left it there, even the path that had turned back from the wrong direction.