The Map Between the Warehouse and the Empty House

Seojin spread the map between the warehouse and the empty house across the floor. The case board held two times. The 04:03 delivery completion photo, and the refrigeration zone power that had risen starting at 04:01. Somewhere between those two, the medicine box might have moved, but the person who moved it and the person who made the photo were still two separate unknowns.

Minwoo connected the warehouse entrance and the shared entryway with blue tape. Song Juhyeok saw the line and reached out to stop him.

"You can't make that route in four minutes."

"You could, with a vehicle."

"A vehicle can't pull up to the shared entryway."

Seojin wrote that down on the route reconstruction sheet. A field technician pushing back wasn't obstruction, it was field knowledge entering the verification process.

The first route ran from the warehouse, loading the medicine box into a vehicle, and moving it to the empty house. The second had the box transferred to a different refrigerated cart inside the warehouse, with a pre positioned delivery vehicle moving separately. The third had the medicine already near the empty house beforehand, with only the completion photo made later.

Seojin applied the same clues to all three routes: the phase change label on the cold pack, the power usage at the shared entryway, and the camera sensor defect on the operations room test phone. Rather than looking for the one route that matched a single clue, she decided to compare which route explained all three at once.

The cold pack label changed color above a certain temperature. It hadn't changed yet when the shipment left the warehouse, and by the time of the completion photo, only the edges had started to turn. The medicine had been exposed to room temperature for a short time, but exactly how many minutes couldn't be read from the label's condition alone.

The shared entryway's power record showed the door opening at 04:02:31 and closing again at 04:03:04. That was thirteen seconds earlier than the timestamp on the app photo taken at the empty house's front door. A door opening meant someone had entered the shared entryway, but there was no confirmation that the person was carrying the medicine.

The test phone had generated the photo at 04:03:17. Its camera sensor had a defect that overexposed one frame, and the bloom resembled the reflected light of the entryway. Whether the photo was a copy or had been taken directly with the test phone couldn't be judged from the sensor defect alone.

Minwoo picked the first route. "They took the box out of the vehicle, carried it to the shared entryway, and took the photo with the test phone."

Song Juhyeok shook his head. "There are stairs between the vehicle and the shared entryway. The timing doesn't match the phase change on the cold pack label."

Seojin didn't take Song Juhyeok's objection as the answer outright. Instead, she prepared a cold pack similar to the actual equipment and moved it between the warehouse's refrigeration zone and the empty house's shared entryway three times. The test compared only temperature change and time, without reproducing the actual execution of the crime.

In the first trial, the cold pack's edges changed in six minutes. The shortest route from the warehouse to the empty house took four minutes forty seconds, and adding the wait time at the shared entryway pushed it past six minutes. The first route was possible, but the photo's timestamp and the label's condition didn't line up exactly.

In the second trial, the box was transferred to an intermediate refrigerated cart. The cart was connected to a power line at the back of the warehouse, and the trip to the shared entryway took three minutes twenty seconds. The label barely changed. But there was no trace of a refrigerated cart charging in the shared entryway's power record on the day of the incident.

In the third trial, the box was placed near the empty house beforehand, and only the photo was taken with the test phone. The label's condition and the photo's timestamp matched, but the power change at the shared entryway at 04:02:31 went unexplained.

Seojin laid the three tables side by side. None of them was perfect. Minwoo said combining the first and third would work, but Seojin said that before combining anything, they needed to confirm each clue came from an independent source.

Song Juhyeok checked the sensor location on the shared entryway's power record. He pointed out the possibility that the power had been consumed not by the door motor but by the compressor in the refrigerated storage unit. The recording device lumped the entire entryway's power into a single line, so the time the door opened and the time the refrigeration equipment ran weren't separated.

Minwoo said, "Then that's not proof the door opened either."

"It's proof power was used," Seojin answered. "The door opening needs to be confirmed again with footage or the door sensor."

Song Juhyeok wasn't satisfied even after hearing that objection accepted. He said the door sensor's battery was low, and part of the 04:02 record was missing. The field technician was directly submitting material that lowered the reliability of his own sensor. Seojin didn't dress up that behavior as cooperation. She recorded the limits of the clue instead.

At three in the afternoon, the original door sensor data arrived from the shared entryway's management server. The door had opened at 04:02:31, but the weight sensor in front of the door detected no object at all between 04:02 and 04:03. Whether a person's weight simply hadn't registered, or the sensor had missed it, still couldn't be determined.

Seojin built a fourth alternative route. In this one, the door had opened for an automatic inspection, the medicine had already been inside the entryway, and only the photo had been made with the test phone. This route explained the shared entryway's power and the photo sensor's defect, but it didn't explain the change in the cold pack label.

Minwoo said, "The clues are telling different stories."

"That's exactly why we can't assume one person did all of it."

Seojin separated the travel time from the direction of approach. The medicine's refrigerated condition pointed to someone moving it within a short window, while the photo's sensor defect pointed to the test phone operating near the entryway. Whether those were two actions by the same person, or split between two different people, was still an open question.

Song Juhyeok pointed to a small refrigerated storage unit inside the warehouse. It was where medicine was kept briefly before the delivery vehicle arrived, and its power usage record showed the door opening at 04:01. The condition of the phase change label matched a scenario where the medicine had been taken out of that unit and moved a short distance.

"Why didn't you mention this storage unit from the start?" Minwoo asked.

"Because the first question was who stole the medicine. I thought if I mentioned the storage unit, you'd think I was protecting someone."

"You are protecting someone, though."

"That's exactly why I'm saying it now. Because the data was confirmed first."

Minwoo heard that answer but didn't treat it as a pardon for Song Juhyeok's earlier silence. He collected the storage unit's door sensor, power record, and cold pack label as separate evidence. If the three records matched, it would confirm the medicine had first moved inside the warehouse, but who had moved it would still remain unanswered.

At six in the evening, the three branching reconstruction tables were complete. The first route was slightly off on time and label, the second didn't match the power record, and the third couldn't explain the shared entryway or the cold pack. The revised route that included the storage unit explained the cold pack, the power, and the photo timestamp all together, but it didn't match the statement of the person who had accessed the operations room test phone.

A new witness emerged. The night duty staff member Yun Hyejin said she had been in the operations room at 04:00 and hadn't touched the test phone, but the revised route required her to have had access. Seojin didn't write her down as the culprit. She recorded her instead as someone whose statement didn't match the physical route.

That night, Minwoo showed the reconstruction table to Song Juhyeok. Rather than asking him to pick the most likely route, he asked which piece of data needed to be preserved most.

Song Juhyeok chose the storage unit's refrigeration power log. He didn't ask that the fact he himself had opened the storage unit be left out of the record. He said that even if the data could hurt him, it had to remain as physical evidence.

Seojin recorded that choice. The field technician had revised the investigation team's route and preserved data that worked against himself. But the duty roster that could be linked to Adil's identity was still held by the protection agency.

Finally, Seojin wrote down the new route. "Possibility that the medicine was first transferred inside the refrigerated storage unit. Shared entryway power requires separate verification of door opening versus storage unit compressor use. Cross check test phone accessor Yun Hyejin's statement against the physical record."

The first hypothesis had narrowed again, and again fallen short of an answer. Instead, the case had shifted into a shape where equipment and timing led, ahead of any person's name. Yun Hyejin came to Gray Thread late at night. She said she hadn't touched the operations room test phone, but Seojin first confirmed the scope of that statement.

"Do you mean you didn't touch the lock screen, or that you didn't create the photo?"

Yun Hyejin took a long time to answer. "I turned the lock screen on for a moment. I didn't take the photo."

She had entered the operations room at 03:58 and left at 04:06. The test phone had woken once in between, and the photo had been created at 04:03. Yun Hyejin said the delivery address had been showing on the screen and she had only meant to check it. But she didn't say why she had turned the screen on.

When Minwoo tried to press her, Seojin stopped him. "Saying you didn't take the photo and saying you didn't look at the screen are two different statements."

Yun Hyejin said all she had seen was the preview of the entryway photo and the delivery number. She also admitted to opening the refrigerated storage unit, but said she hadn't moved the medicine box. Her statement partially matched the revised route, but the question of who had created the photo remained empty.

Seojin separated Yun Hyejin's access into physical records: the time the screen turned on, the storage unit's power usage, and the time the photo was created. The three times were close together, but none of them proved the other.

Song Juhyeok heard that statement and still didn't say Adil's name. Instead, he asked that they confirm with the protection agency what personal information had been on the screen Yun Hyejin had seen. It was to make sure one person's information wasn't newly exposed through another person's statement.

Minwoo added Yun Hyejin's access to the test phone evidence list, but didn't confirm her as a suspect. Seojin looked at the table and revised a line. "The new witness's statement partially matches the route, but the causal link to the photo's creation remains unconfirmed."

As the night deepened, the timeframes of the storage unit's power log and the phase change label lined up with each other. It grew more likely that the medicine had moved first inside the warehouse, and that the photo and token had then been created on a separate device afterward. The case now required not one hand, but two separate points of access.