An old scar

This process can take quite a long time.

The perpetrator may have stolen hard drives from the monitoring room during this period, and may have done other things as well.

She took the nylon cable ties and towel from Lao Fang's hand and looked through them.

The cable ties are industrial grade, from the same brand as those used in previous cases—eight millimeters wide, white, with neat edges and the same cutting method.

The towel was just a regular white cotton towel, without any brand label.

These are not the key points; the key points are the deceased's pupils and conjunctiva.

She stood up, returned the evidence bag to Lao Fang, and asked him if he had retrieved Gong Jiafu's recent work schedule and any unusual records.

Old Fang opened his notebook and said he had asked the transfer station manager and several colleagues. Gong Jiafu had been working regular shifts for the past month, arriving and leaving get off work on time, without taking any leave, and without having any conflicts with anyone.

He wasn't supposed to be on the night shift yesterday—he voluntarily switched shifts with a colleague, saying he had some personal matters to attend to that night.

The colleague who took over the shift was named Cui Dahu, and he was from the same hometown as Gong Jiafu.

Cui Dahu said that when Gong Jiafu asked him to switch shifts, he seemed quite relaxed. He didn't say what it was about, only that "someone is coming tonight."

"Someone's coming tonight." Jiang Ruolan wrote this sentence in her notebook, circled it, and continued, "Is the person male or female? What's their name? What time are they coming? What do they want?" Gong Jiafu didn't tell anyone these details. He kept them to himself, voluntarily swapped night shifts with his fellow villager, and then waited for someone in the empty warehouse late at night. This person came, killed him, and took the hard drive from the surveillance room. This means that the very existence of this person in the hard drive's records was evidence that couldn't be preserved.

Lu Zheng took a newly printed copy of the phone call log from the technician, quickly scanned it, and then frowned:

"Gong Jiafu's mobile phone made four calls to an unknown number in the past week, each time after 9 p.m. The calls were short, the shortest being less than a minute and the longest being a little over three minutes. This number was not registered under a real name and was one of those prepaid cards that can be bought at roadside newsstands. The last call was last night, less than an hour before the incident."

Have you checked the signal tracking for this number?

"They're investigating. The technical department said this number is only turned on at night and turned off during the day. The signal only appears between a few base stations within a two-kilometer radius of the Chengdong Logistics Park. He always calls Gong Jiafu between 8:30 and 9:00 PM, and then turns off the phone. It's a one-time use number specifically for contacting Gong Jiafu; it's used and then discarded, so we'll never know the content of the calls. The last call lasted for nearly four minutes, longer than the previous ones. After hanging up, Gong Jiafu didn't call anyone or report it to the police. He calmly waited until the end."

"This shows that he knows that person and trusts him. Someone who would ask him to switch night shifts, talk on the phone for four minutes, and not call the police after hanging up must be someone he knows very well. Investigate his fellow villagers, his former coworkers at the logistics park, and people who have frequently interacted with him in the past three years."

Jiang Ruolan closed her notebook and asked Lao Fang to continue investigating the personnel inside the logistics park, focusing on Gong Jiafu's fellow villagers or fellow townsmen, especially those working in the logistics park or other freight transfer stations.

Then she turned and walked towards the warehouse door, saying to Lu Zheng as she went:

"The killer's method of prying the hard drive from the monitoring room was very professional—he knew the location of the monitoring room, knew the work schedule of the security guard on duty, and knew to use a key to open the door instead of forcibly picking the lock. He did it during the few minutes when the security guard was out on patrol."

But he's not a god—he couldn't possibly know out of thin air when the security guards would leave their posts. Either he had scouted the location beforehand and observed the guards' shift schedule, or someone on the inside had told him that the guards had been drinking the night before and were prone to dozing off.

There must be someone in the logistics park who knows the killer, or at least has seen the killer scout the area. Review the surveillance footage from all entrances and exits of the logistics park and investigate all unfamiliar people and vehicles that have entered or exited the park in the past week, especially those appearing after 8 PM.

Furthermore, breaking into a surveillance system requires certain skills—an ordinary person might not know how to quickly remove the hard drive from a running surveillance system. The perpetrator must have had experience in security or equipment maintenance. Check if Gong Jiafu has anyone with this background.

Before dawn, technicians completely reconstructed the base station location trajectories of the last four unknown calls in Gong Jiafu's phone call log, detailing the base station number and coverage area of ​​each call.

The four calls came from the same number, spread across four nights in the past week. Although each call was very short—the shortest being only 52 seconds—the geographical locations of the signal sources were highly consistent.

The technician marked the four signal points on the electronic map, all of which were located in an area southeast of the Chengdong Logistics Park.

Narrowing the scope further, all signals were concentrated near a residential building slated for demolition in the old city area of ​​eastern Chengdu.

The old town area is less than two kilometers from the logistics park, separated by an abandoned industrial site and an old riverbed that has been dry for many years. It takes less than ten minutes to get there by electric bike.

If the perpetrator turns off his phone after each call, his movements after the call cannot be tracked by the base station signal. This fixed location where the phone is turned off is likely his temporary lodging before and after each contact with Gong Jiafu, or the location where he stored the tools used in the crime.

Lu Zheng projected the electronic map onto the conference room screen and used a laser pointer to draw a circle around the location of the residential building slated for demolition:

"Gong Jiafu's wife said that he has been standing alone on the balcony smoking every night for the past week, which he never did before. When his wife asked him what was wrong, he said nothing. The call times of this prepaid number on his phone highly coincided with the times when Gong Jiafu was standing on the balcony smoking. He was waiting for that person's call."

"What's the current status of that building slated for demolition? Is anyone living there?" Jiang Ruolan asked.

Zhao Rui flipped through the investigation records in his hand:

"That building is the last remaining building in the old residential area of ​​the cotton mill in the east of the city. It was part of the same demolition project as the ruins involved in the cases of Duan Changhe and Qu Yongfu. Most of the residents have already moved out, and only a few households are still at an impasse."

We visited a house and found an elderly woman surnamed Zhou living on the east side of the first floor. She said that recently a strange man had been appearing near the building at night, riding an old electric scooter with a toolbox strapped to the back seat.

The old woman thought he was a plumber, but the man never went into any rooms. He would just park his electric scooter in the hallway, sit for a while in the stairwell, and then leave. The old woman said the man was probably in his forties, not very tall, rather thin, and wearing dark work clothes. She couldn't see his face clearly, but there was one very noticeable feature—an old scar above his left eyebrow.

...............