The first useful answer in January came on a day Yanchuan had promised not to spend waiting for one.
He was presenting a calculation of summer cooling demand. Outside the meeting room, rain had turned the windows gray. Chen had asked him to show the assumptions rather than only the result, and Yanchuan was halfway through the upper limit when his phone lit up beside the notebook.
An: The annex has a visitor register.
He turned the phone over and finished his sentence.
Afterward, in the stairwell, he called her. The case inquiry had reached the service compound’s administrative office. Staff had retained a bound visitor book for October and an electronic summary prepared at the end of each shift. Both were being checked against other records.
“Does it have his name?”
“There’s an entry under his name. Friday, the thirtieth.”
“Who wrote it?”
“They haven’t established that yet.”
Yanchuan sat on the lowest stair. Someone came through the door carrying printer paper and stepped around him without comment.
“Why didn’t anyone tell us?”
“Because until last month we didn’t know which office to ask.”
He understood. He wished he did not.
The limited extract arrived in the afternoon. It showed a photograph of a handwritten page. At 15:06 on October 30, someone had entered LIN YANSHENG in block capitals. The purpose column said maintenance record. The signature box held two short strokes too blurred to be meaningful. A departure time was not visible in the portion shared.
The electronic summary had the same name, the same time, and the same purpose. For a few seconds Yanchuan allowed the agreement to steady him. Two records had survived. Two ways of finding the same man.
He sent the extracts to Mei.
She called from a corridor at work. Behind her a door kept closing badly.
“Where does the electronic summary get its data?”
“From the visitor desk, I think.”
“You think. Does it say?”
“No.”
“Then you may have one record presented twice.”
He enlarged the photograph. In the handwritten purpose column, the final letter of record had touched the dividing rule. The electronic version rendered the abbreviation as records, plural. There was a clerk’s interpretation somewhere between the two, but no evidence that another person had seen the visitor.
“That’s still a record,” he said.
“Yes. It is useful. You were about to count it as two.”
He remembered the hotel’s checkout charge. Luo had described a settled account as a man walking through a door. Yanchuan had spent days correcting that claim. Now he had nearly done the same thing in the direction he wanted.
“I made the error twice.”
“You noticed the second time,” Mei said. “Make a note of that too.”
He did not want to make a note of it. He wanted to know whether his brother had stood at a counter on Friday afternoon, whether he had been tired, whether he had carried the battered folder in the equipment photograph.
He wanted the strokes in the signature box to become a hand.
At the scheduled evening review, An sat at her dining table with the school calendar beside the laptop. Their son was behind her building an upper level on his wooden bridge, supported for the moment by a ruler.
Yanchuan had prepared six questions. An read them and crossed out the two that began Why did the office conceal.
“They had the book for months,” he said.
“They had a book. We didn’t know it existed. Those are different statements.”
“I know.”
“Then ask what happened, not why someone did it to us.”
“You’ve had months to think that way,” he said.
An looked at him over the school calendar. “I’ve had months to ask our son why his father isn’t home. You don’t get to tell me what thinking has cost.”
He moved the two crossed-out questions to another sheet. She did not apologize for crossing them out, and he did not ask her to.
He opened a blank page.
They asked for the identity of the person making the entry, whether identification had been checked, whether a visitor pass was issued, and whether a departure had been recorded somewhere else. They asked whether the electronic summary was copied directly from the register. Wanjiru agreed to put the questions through the investigator, who could seek the original without exposing unrelated visitors.
The last question cost them several minutes: could the record be compared with the hotel and transport chronology without assuming the same traveller appeared in each?
“Write that exactly,” An said.
When the meeting ended, Yanchuan stayed at the table. He had been thirteen when he last watched Yansheng write both their names on a parcel for their aunt. His brother’s characters had leaned forward as if late for something. He could remember the movement so clearly that he almost saw it in two indistinct marks beneath the visitor’s name.
The marks did not become clearer when he looked again.
He called his father. Jianming asked at once whether the police had found a confirmed sighting.
“Not yet,” Yanchuan said. “There may be a visitor entry from Friday.”
“May be?”
“The entry exists. We don’t know who used the name.”
His father was quiet for a while. In the background a radio announced rain in Wuhan.
“Then tell me when they know.”
Afterward, Yanchuan added a line to the chronology: October 30, 15:06 — entry under Yansheng’s name in service-compound visitor register; presence not independently verified. Beneath it he wrote that the electronic summary probably derived from the same entry. He did not turn two copies into two witnesses.
The next morning Chen returned the summer-demand chart with one sentence circled. Yanchuan had written that the system would meet the forecast. Chen wanted the tested limits stated beside the promise.
He made the correction before opening the family document.
The last confirmed contact remained Thursday, October 29. That date still stood. Friday now had a question with a time attached to it, and someone who might be able to answer.
He copied the entry into his notebook by hand, including the words presence not independently verified. The date looked no less precise for the warning beneath it.