In the evening, Lin Dongxue and Little Li went to Chen Shi's house. Seeing that Lin Dongxue had found the building easily, Little Li asked, "Dongxue, do you come here often?"

Lin Dongxue said bashfully, "Not too often!"

Hearing the knock on the door, Chen Shi opened it. Lin Dongxue saw a bicycle placed upside down on the floor. It was very similar to the model that the deceased rode. Lin Dongxue asked in surprise, "Are you doing an experiment?"

"Yeah, I reckon that the bicycle at the scene would have been damaged beyond recognition, so I bought one myself, to see if the 'murder hook' really works."

"What's the conclusion?"

"I'll talk about it later. Come and look at this."

Lin Dongxue then discovered that Chen Shi was wearing gloves. The three of them went to Tao Yueyue's bedroom. Little Li looked around and said in admiration, "Brother Chen must normally dote on this girl."

"I don't think I paid enough attention to her." Chen Shi said sadly, and then took out something. It was a crumpled piece of paper with some spray paint on it. There was a small screw-shaped unsprayed part in the middle.

Lin Dongxue didn’t quite understand, until Chen Shi took out a roll of wire and a bottle of spray paint. “Yueyue seems to have sprayed this 'murder hook' with spray paint, probably to prevent the color contrast from being obvious. Is the bicycle of the deceased this color?"

"Yes, it's pure black... Indeed, if there’s a twisted wire on the pure black bicycle frame, it would be too conspicuous. She even took this kind of detail into account?"

Chen Shi sighed, "Yueyue is sometimes horrifyingly meticulous. However, she is still inexperienced after all. I should be grateful for that. She just threw the piece of paper that had been placed underneath into the wastebasket, but she didn’t dispose of it. Based on the shape, this is the size and appearance of the 'murder hook' she made."

Lin Dongxue fell deep in thought. Her gaze fell on Chen Shi's face inadvertently. Chen Shi said, "I know what you’re thinking. 'This is not false evidence that he created, right?' Don't worry, Yueyue's fingerprints should be on it. You can take it back for testing."

"What are you thinking? Why would I doubt you? If you didn’t want her to be arrested, you wouldn't have told me in the beginning."

"In that case, what I say next may sound more like exonerating Yueyue. After my repeated experiments, I found that the efficiency of the 'murder hook' isn’t very high! Please come to the living room, officers."

Based on the traces on the paper, Chen Shi had twisted a "murder hook" out of the wire. He said, "This thing was hung on the bicycle frame like this, maintaining a delicate distance from the spokes. If the bicycle turns a little, the wheel spokes revolving at a high speed would be caught by the wire hook, and then the front wheel will stop suddenly, causing the whole bike to topple forward... Theoretically!"

Lin Dongxue asked, "But what about in reality?"

Chen Shi continued, "After my repeated experiment, I found that Yueyue had underestimated the power of the wheels. The small wire hook can't grip the spokes..." As he said this, he fixed the "murder hook" to the frame, cranked the pedal with his hands, and let the wheels turn at high speed. Then he pulled the handlebars slightly.

When the spokes touched the wire hook, the entire "murder hook" was torn off. Chen Shi stopped. "Look, it can't hook the spokes at all. I roughly calculated that the angular velocity of a spoke is 40 degrees to 180 degrees per second. It takes about two seconds to make a full circle during normal cycling. This speed is very fast. Sometimes foreign objects would get caught and they would either be broken off or drawn into the spokes. It’s impossible for a small handmade hook like this to stop its motion."

Little Li commented, "When I was a kid, I rode on my father's Phoenix-brand bicycle. Sometimes I accidentally got my feet caught in the wheels. Usually, the shoes would get drawn in and the wheels wouldn't stop right away. Of course, I've also heard of some children wearing sandals in summer who fractured their toes. The power of the wheels is indeed great."

Lin Dongxue pondered, "Let me borrow a computer."

She played the surveillance footage she found that afternoon. Chen Shi, who had grasped a glimmer of hope, saw the scene and suddenly fell silent. Lin Dongxue said, "Old Chen, I really didn't want to refute you. At the moment of the traffic accident, the bicycle of the deceased indeed showed signs of being affected by external forces. Your experimental conclusions are still in doubt... You won't mind if I say this, right?"

"Of course I don't mind, I just want to clarify the facts... but this video didn't capture the key moment?"

"The Traffic Management Bureau has a queue of cases right now. It’s very troublesome to get the surveillance footage transferred. It can’t be helped that this minor case happened to coincide with Zhou Xiao's major case!"

Little Li suggested, "Shouldn’t we find this little girl first? Regardless of whether she has committed a crime, it’s definitely not safe for her to stay outside for three days... By the way, she still has to take the junior high examination soon as well, but she’s gone missing at this critical juncture?"

Chen Shi said, "I have already asked friends to help me find her. When she left, she had about 500 yuan in cash on her. The mobile phone, school campus card, and student ID were all left at home. She had brought a school bag with her, some clothes, and a copy of The Time Machine…"

"Is there anything special about that book?" Little Li asked.

"There's nothing special, she just hadn't finished reading it..." Chen Shi said.

"When you say ‘friends’, do you mean..." Lin Dongxue asked.

"Yes, it's the two of them. They’re really good at finding people, and they like Yueyue very much. They will definitely try their best to find her."

"But aren't they looking for Miss Gu right now? Is there enough manpower? Do they need help?" Lin Dongxue didn't know about Gu You's murder, and still thought she was missing at the moment.

"They have their own helpers too." Chen Shi diverted the topic. "The difficult part is that Yueyue is too smart. If she really wants to hide or leave Long'an, it would be very difficult to find her through normal channels."

"If, and I mean if, she really didn't kill anyone, we should let her know about it through the media, and Yueyue will come back by herself... This is the best outcome that I can think of!" Lin Dongxue said.

Chen Shi stared at the footage that was being played repeatedly. "I believe she didn’t kill him. This isn’t the guardian's wishful thinking. Intuition and experience tell me that she can't kill people with this little trick. There’s another reason for this boy's death!"

"Let's go to the scene later and see if we can find any evidence!" Lin Dongxue suggested.

Chen Shi looked at the table and chairs in the living room, recalling the scene of how the two of them sat there eating dinner. If Yueyue could return safe and sound, he must teach her a lesson.

At this moment, Lin Dongxue turned on the lights. "The house is so dark and the atmosphere is too depressing."

Since they were going out together at night, the three of them stayed at the house. Little Li drank a glass of water, stood up, and said, "I'll take the evidence back to the bureau. The people in the evidence room shouldn't have gotten off work yet."

"Just go tomorrow." Lin Dongxue said.

"Fool!" Little Li whispered, "I'm letting you two be alone for a while. I won't be the third wheel here anymore. I’ll drop by the hospital to see Xiaodong, and I’ll be back here just after 10:00."