Attending ex-girlfriend's wedding, arresting the groom's officer on the spot

“Unusual…” Liu Fang thought for a moment, “A week before he went missing, he came back with injuries. He said he had a fight with his coworker Li Tiezhu because Li Tiezhu owed him five thousand yuan and hadn’t paid it back. He also said that Li Tiezhu threatened him that if he forced him to pay back the money, he would be rude to him.”

"Li Tiezhu?" Lu Chuan's eyes lit up. "Do you know where Li Tiezhu is? What does he look like?"

“I know him. He works at a construction site in the eastern suburbs. He has a scar on his left cheek from a fight in the past,” Liu Fang said. “I went to see him and asked him if he had ever seen the sea. He said no and kicked me out.”

Li Tiezhu, with a scar on his left cheek, perfectly matched the description of the suspicious man given by Master Li! Lu Chuan immediately dispatched his team to the construction site in the eastern suburbs to apprehend Li Tiezhu. Meanwhile, news came from the technical department that the DNA from the hair found between the deceased's fingers failed to match Liu Fang's DNA, indicating it wasn't Liu Fang's. However, the DNA typing of the cigarette butt had been completed and was being compared with the national database.

At one o'clock in the morning, the arresting team reported that Li Tiezhu had been successfully apprehended and was on his way back to the branch office. Lu Chuan stood by the office window, looking at the night sky outside. Although it was still gloomy, he knew that the dawn of the truth was not far away. The deceased was very likely Zhang Dahai, and Li Tiezhu was a prime suspect, but the evidence he had was not yet sufficient, requiring further interrogation and evidence collection.

When Li Tiezhu was brought into the interrogation room, Lu Chuan personally conducted the interrogation. Faced with Lu Chuan's questions, Li Tiezhu initially denied everything, saying he didn't know Zhang Dahai and had never been to the urban village in the western suburbs. But when Lu Chuan produced the photo of the "Double Happiness" cigarette butt, his expression instantly changed. "I smoked that cigarette, but I didn't kill anyone. Zhang Dahai's death has nothing to do with me!"

"Then why did you threaten Zhang Dahai? Why did you immediately change construction sites after he disappeared?" Lu Chuan pressed, his gaze sharp as a knife.

Li Tiezhu's psychological defenses began to crumble, his hands trembling slightly: "I did owe him five thousand yuan, and I threatened him, but I didn't kill him. One night three months ago, I ran into him in an urban village in the western suburbs. He forced me to pay back the money, and we argued and even fought. I pushed him to the ground and ran away, and I haven't seen him since. I changed construction sites because I was afraid he would come after me for money again, not because I killed him."

"You're lying!" Lu Chuan slammed his hand on the table. "The cigarette butts found at the scene were yours. How do you explain that? You say you didn't kill him, but can anyone prove that?"

Li Tiezhu lowered his head and remained silent for a long time before whispering, "No one can prove it. It was too late, and there was no one around. But I really didn't kill him. He was still alive when I ran away, but he had a cut on his forehead and was bleeding."

Just then, crucial information came from the forensic department: the DNA on the cigarette butt matched Li Tiezhu's DNA perfectly, and the DNA from the skin flakes under the victim's fingernails also partially matched Li Tiezhu's, indicating that the two had indeed fought. However, the fiber composition of the ligature marks on the victim's wrist did not match the fibers of the clothing Li Tiezhu was wearing, and the size 42 footprints found at the scene did not match Li Tiezhu's size 41 shoes. This result brought the interrogation to a stalemate. Li Tiezhu admitted to having an argument and fight with Zhang Dahai, but denied killing him, and the evidence at the scene also indicated that a second person might have been involved. Lu Chuan realized that this case might be more complicated than he had imagined, and Li Tiezhu might just be a participant, not the real murderer.

The sky outside the window was gradually turning a pale white, and a new day had begun. Lu Chuan walked out of the interrogation room and saw Yang Lin and Yang Sen waiting for him with a new investigation report. "Captain Lu, we found a new clue on that key. The 'Fu' character pattern on the key handle is a keychain exclusive to the 'Happiness Community' in this city. This community is located near the urban village in the western suburbs. It was demolished three years ago, but some residents still haven't moved out."

"Happiness Community?" Lu Chuan's eyes lit up. "Immediately send people to Happiness Community to investigate, focusing on Zhang Dahai and Li Tiezhu's social connections there. Also, retrieve the surveillance footage from Happiness Community again to see if there were any unusual occurrences three months ago."

Although the investigation remains fraught with twists and turns, new clues have emerged. Lu Chuan knows that as long as they persevere and leave no detail overlooked, they will surely find the real killer of Zhang Dahai and give the deceased and his family justice. The clues scattered throughout the ruins will eventually piece together the complete truth, allowing justice to be served.

At seven o'clock in the morning, Zhang Hui led four team members to Xingfu Residential Area. Calling it a residential area was a stretch; it consisted of half a section of old buildings that hadn't been completely demolished and a cluster of makeshift prefabricated houses. A few strands of clothing hung to dry among the broken walls, and the air reeked of coal smoke and household garbage. Old Zhao, the community police officer responsible for meeting them, was already waiting at the entrance, clutching a yellowed list of residents, his face full of worry.

“Team Leader Zhang, this neighborhood was included in the demolition plan three years ago. Most of the residents moved to the resettlement area, and now there are only seventeen households left. They are either elderly people living alone or odd jobs, and the turnover rate is very high.” Old Zhao pointed to a three-story building with mottled walls in the distance. “Zhang Dahai used to live in Unit 2, Room 101. After he disappeared, his wife Liu Fang moved to a relative’s house in the suburbs. The house has been empty ever since, and the doors and windows are not locked properly. Occasionally, scavengers go in and rummage through things.”

Zhang Hui looked up and saw that a piece of the window glass in room 101 was broken and simply covered with a plastic sheet. The iron lock on the door handle was so rusted that it revealed a gap when pulled lightly. "Investigate the scene first, and be careful to preserve the traces so that they are not destroyed by the previous scavengers." He put on gloves and signaled to his team members to carefully open the door with tools to avoid leaving new fingerprints.

The door creaked open, releasing a damp, musty smell mixed with the odor of smoke. The room was small, a one-bedroom apartment with sparse furniture: a wooden bed with uneven legs, a few moldy old clothes piled on the bed frame; a wardrobe with peeling paint, its door wide open and empty; the only folding table leaning against the corner, scattered with several empty beer bottles, a deck of cards with a chipped corner, and half a bowl of spoiled instant noodles. There were several messy scratches on the floor, it was unclear whether they were left by Zhang Dahai before his death or by scavengers later. "Yang Lei, focus on collecting fingerprints from the bed edge, table corner, and wardrobe handle, regardless of whether they are new or old, collect them for comparison." Zhang Hui squatted down, his gaze sweeping over the clutter piled up under the table.

Among a pile of crumpled waste paper and cigarette butts, Zhang Hui used tweezers to pick up a crumpled piece of paper. Unfolding it, he found half an IOU, with only the blurry words "Owes RMB 20,000" printed on it. The borrower's signature had been torn off. (End of Chapter)