The police quickly launched an investigation into Cui Hao's whereabouts in Xilin before his death. Cui Hao arrived in Xilin City by plane at noon on February 1 this year, and reported to the conference group of the Acoustic Academic Exchange Conference in the afternoon of the same day, and stayed in the hotel. That night, he went to the Nanfeng Guqin Workshop to find Nanwei. After that, Cui Hao attended the meeting on time every day. According to the person in charge of the conference affairs team, on the evening of February 13, the day before the end of the meeting, he received a call from Cui Hao, saying that he had to return to the UK early because of urgent matters, and checked out early the next morning. The people in the conference team thought that he had returned to China, so they never contacted him again.

The hotel's surveillance video data is only stored for a month, and it is no longer possible to find clues through the surveillance video. The case-handling staff asked Xiao Li, a female staff member at the front desk of the hotel who was on duty at the time, to confirm, and after checking the information, Xiao Li confirmed that at about 6 o'clock in the morning on February 14, Cui Hao, who participated in the acoustic academic research conference, checked out. But because more than three months have passed, she has a vague impression of the other party's appearance, and she can't confirm whether it is the person in the restored photo, but she only remembers that the person is wearing a very special ring on his hand, which caught her attention. The ring was in the shape of a butterfly, and she also praised the beauty of the ring, and the gentleman said that because his lover liked butterflies, he made a special pair of rings. It happened to be Valentine's Day that day, and Xiao Li thought he was in a hurry to go back to celebrate the holiday with his lover, and wished him a happy Valentine's Day.

Nan Wei confirmed that she likes butterflies very much, so when they were in love, Cui Hao specially ordered a pair of butterfly-shaped rings, and when Cui Hao came back to see her this time, she was still wearing the ring on her hand, and her own ring had already been thrown away.

According to the current situation, Cui Hao last appeared when he checked out in the early morning of February 14, and then disappeared. To transport the body to the mountain behind the Nanfeng Guqin Cultural Village for burial, the only way to do so is by water. The dock surveillance video data can be stored for a long time, and the investigators urgently reviewed the surveillance video of the pier and found that at 7:10 p.m. on February 15, the car owner Nan Wei's vehicle drove into the Fisherman's Wharf parking lot, and a woman got out of the car, opened the trunk, took off a blue suitcase, and pulled the suitcase to the dock. The woman covered her face and mouth with a headscarf, wore sunglasses, wore a very loose long coat, and deliberately avoided surveillance cameras, unable to distinguish her face and figure. It wasn't until near noon the next day that the woman reappeared in the parking lot and drove away.

The investigators also found the driver of the small runabout rented by the woman, and the woman's strange dress left a deep impression on the driver, who remembered that the woman was carrying a large blue suitcase, and the destination was Li Island. When I went, I booked a return trip the next morning, and got on the speedboat to return the next morning according to the agreed time.

Nanwei denied that the woman was her, saying that her car keys had been lost and that someone must have taken her car. But she was unable to provide an alibi from the evening of February 15 to noon the next day, when she was alone with her children at home and there was no one else to attest. Chen Yufei invited Cheng Yijie to identify the surveillance video, and Cheng Yijie believed that the woman in the picture was not Nan Wei. But based on his statement alone, he can't clear Nanwei's suspicion. Of course, there is not enough evidence to prove that Nan Wei is the murderer who killed Cui Hao and destroyed the body.

"I also don't think that woman is Nanwei." In private, Chen Yufei said her personal thoughts to Cheng Yijie, "When she saw the restored photos that day, the shock and sadness didn't seem to be pretended. They must have loved each other very much, Cui Hao never forgot Nan Wei, Nan Wei also can't forget Cui Hao, the relationship is still there, not to mention, the misunderstanding between them has been solved, how can she do it. ”

"I'm more interested in who the woman who pretended to be Nanwei is." Cheng Yijie believes that he will not look away, and the woman in the surveillance screen is not Nan Wei, but someone pretending to be Nan Wei to lead the suspicion to her.

Chen Yufei told Cheng Yijie about the results of the investigation so far, and Cheng Yijie fell into thought, until dinner in the evening, his mind was still on the case.

"What's wrong with you, absent-minded." Mu Qingcheng looked at him strangely.

Today is Friday, and Cheng Yijie asked Cheng Lang to prepare a sumptuous dinner and brought Mu Qingcheng to his home for dinner. "I'm thinking about the case of Cui Hao's murder." He said.

Mu Qingcheng pursed his lips slightly. "When eating, don't think about that, it affects your appetite."

"Okay, don't think about it, concentrate on eating." Cheng Yijie readily agreed, picked up the rice bowl, and ate in a big gulp.

As soon as the two finished dinner, Cheng Lang came back. Xu Youran has something, he didn't have a date tonight, he just went to get photos. He took a lot of good photos in Nanfeng Guqin Cultural Village, and picked one of the most satisfying ones, took it to be developed, enlarged, framed, and prepared to be hung on the wall.

The framed large photo attracted the attention of Cheng Yijie and Mu Qingcheng, and the two walked up to admire it. In the picture, the sun shines brightly, and the mountains, trees, etc., are all covered with a golden light, and the color of the photo is saturated, clear and transparent, and pleasing to the eye.

"At that time, I was taking pictures at noon, and I was burned to death by the sun. Luckily, I brought a prime lens, which is sharper than a zoom lens and does a better job of handling flare and internal reflections. Cheng Lang popularized the knowledge of photography by the way.

Cheng Yijie took a closer look and found that the small mountain col on the picture happened to be the place where Ni Yanlin was killed. I heard Cheng Lang say: "It's really hard to take such a satisfactory photo, not only in the sun, but also a truck parked on the mountain col, blocking there, no matter how you take it, you can't avoid the truck, but fortunately, the truck drove away quickly, and finally found a good angle." ”

"Trucks?" Cheng Yijie stared at the photo for a while, and suddenly a flash of inspiration occurred in his mind, "Do you remember the approximate time when this photo was taken?" ”

Cheng Lang thought about it and said, after he left the hotel, he looked for Xu Youran everywhere, and when he arrived at Xiaoshan Pass, he saw his watch, it was about 1:10, plus the time he spent squatting there, it should have been nearly half past one to take this satisfactory photo.

"Did you take any pictures of the truck?" Cheng Yijie asked.

Cheng Lang said yes, went upstairs and hugged a laptop down, opened it to look up, and found a few photos of the truck.

"I'm going to go to Nanfeng Guqin Cultural Village again tomorrow." After Cheng Yijie carefully studied the photos, he immediately made a decision, "Little Orange, come with me." ”

"Okay." Mu Qingcheng agreed without much thought, she knew that Cheng Yijie must have made some new discoveries about the case, and she was willing to accompany him and watch him use his wisdom and display his talents, which was a very happy thing.

"Why go again?" Cheng Lang was puzzled, "Although that place is good, it's not worth going to again in such a short time." ”

"I'm going to get things done." Cheng Yijie kept it secret, "As for what to do, I can't tell you yet." ”

Cheng Lang deliberately misinterpreted what he meant. "Doing things, I understand, you want to take your sister-in-law to fight in the mountains and forests."

"Stinky boy, not right-minded." Cheng Yijie reprimanded.

"Less, I'm speaking your mind." Cheng Lang smiled.

Cheng Yijie looked at Mu Qingcheng, she twisted her head and ran up the stairs, he smiled lightly and followed.

The next day, Cheng Yijie and Mu Qingcheng went to Nanfeng Guqin Cultural Village again. They rented a speedboat by themselves, and Cheng Yijie chartered it back and forth, letting the speedboat driver wait on the shore.

The two crept to the col near the hotel without alerting anyone.

Cheng Yijie had asked Chen Yufei to send him photos of the scene of Ni Yanlin's death, as well as photos of Ni Yanlin's unfinished sketches, and Chen Yufei also found the driver of the truck parked there at the time. Previously, she had also questioned the driver when investigating the murder of Ni Yanlin, and the truck was transported to the island by transport ship during the construction of the Nanfeng Guqin Cultural Village, and has been used in the cultural village since then. Some of the hotel's exterior landscaping had not yet been completed, so trucks were used, but there were other workers on the truck besides the driver, and after moving the required building materials to their destinations, they drove away, and several people were working together during that time, so the suspicion was ruled out. According to the driver, they drove to the top of the small mountain pass at about 12:40 and stayed for about 40 minutes, that is, they left at about 1:20, which was the same time as Cheng Lang said.

Cheng Yijie asked Mu Qingcheng to stand in the position where Ni Yanlin was when she died, and he stood opposite her, looking up to observe the surrounding environment.

"Did you find anything?" Mu Qingcheng asked.

Cheng Yijie nodded. "The biggest problem that plagues the police with Ni Yanlin's murder is that the range of presumption of death is too large, from 1 p.m. to 4 p.m., and the alibi is relatively vague. Thanks to Cheng Lang's prompt, the time range can now be narrowed. He was full of confidence, "Ni Yanlin arrived at the Xiaoshan Col for a photo, it was around 12:45, it was the time when the sun was the strongest at noon, and it was an open area again, and there was no shelter around, but Ni Yanlin was sitting under the sun sketching, which was unreasonable. Now I understand why, it's the truck. You come to me. ”

Mu Qingcheng took a few steps forward, turned around, and looked in the direction of Cheng Yijie's finger, which was where the truck was parked at that time.

The truck cast a shadow, and Ni Yanlin chose to sit in the shadow cast by the truck, just enough to shield her from the strong sunlight. Judging from her unfinished sketches, it is also certain that she is sitting in this position, depicting the scenery opposite. "However, the truck drove away at about 1:20 a.m., the shadows disappeared, and Ni Yanlin was exposed to the strong sunlight." She didn't leave, and she was in the same spot until the body was found. ”