In the interrogation room, sanitation worker Zhang Guofeng sat nervously on the chair, his eyes darting around, looking guilty as if he had done something wrong.
Sun Guangtian frowned when he saw him.
He exchanged a glance with Fang Rui, and they both had the same thought: this man couldn't be the killer. A serial killer's psychological fortitude couldn't be this poor!
"Where were you between 6 PM and 8 PM on the 28th?" Sun Guangtian asked.
"I was resting at home that day."
"Are you sure?"
"Ah, no, I wasn't off that day, I was on shift. I went to clean outside Jiangzhou University's gate."
"You'd better tell the truth." Sun Guangtian's tone was a bit impatient.
Zhang Guofeng looked aggrieved: "I am telling the truth. I'm an honest person, why would I lie? I haven't done anything wrong!"
"Your vehicle arrived near the school just after 6 PM, but you didn't start cleaning at the school gate until after 8 PM. What were you doing during that time?"
"I..." Zhang Guofeng hemmed and hawed for a while, finally coming up with an excuse, "I went to the bathroom. I had an upset stomach that day, so I relieved myself in the woods."
"Where exactly? Take us there now."
"I... I forgot."
Seeing his face turn red, Sun Guangtian said, "Just be honest. Were you gambling or visiting a prostitute?"
Zhang Guofeng's voice rose a few pitches: "What prostitute? How can it be called prostitution if I'm visiting my old flame?"
"Old flame?"
"My wife is extremely strict, so I can only meet my old flame under the pretense of going out to clean. Otherwise, she'd beat me to death."
Zhang Guofeng shrank his neck, "I usually leave early with the garbage truck, then park it at the edge of the small forest. Then I cut through the woods and take a shortcut to my lover's house. I don't dare drive directly to her place, afraid someone might see my vehicle parked under her building and tell my wife. That day I went to her house, she can vouch for me."
"Does anyone else have the keys to that three-wheeled vehicle?" Sun Guangtian asked.
"I'm the only one with the keys."
"Do you often go for these trysts?"
"What do you mean trysts? I just go there for massages. I go about two or three times a month. Sometimes five or six times when it's more frequent."
"Does anyone know about this habit of yours?"
"Nobody knows! Otherwise, my wife would beat me to death. I always sneak off to see her secretly."
Sun Guangtian contacted Zhang Guofeng's secret lover, who confirmed that during that time period, Zhang Guofeng was indeed with her.
Surveillance cameras near her house also proved that Zhang Guofeng had jogged all the way to her place. So he didn't have time to dig a hole and bury a body.
His suspicion was temporarily cleared.
After the interrogation, it was already past 11 PM.
Song Haiyang and his team were frustrated that the suspect they had worked so hard to find turned out not to be the killer. They had been reviewing surveillance footage day and night, only to have it turn out to be a false lead.
Someone complained, "I haven't closed my eyes for days, I'm exhausted, and we didn't find anything."
"Exactly, we're human, not machines. We need rest!"
Sun Guangtian's face turned ashen. He told everyone, "You all go home and rest."
Everyone immediately packed up and left.
Only Sun Guangtian and Fang Rui remained in the office. He leaned against the window and started smoking again.
Fang Rui saw his state and wanted to comfort him, but was interrupted: "Fang Rui, you're not staying behind to watch me make a fool of myself, are you?"
"Of course not. This is how investigations go. Often you might investigate for half a month and find nothing. Then suddenly you might get a lead and catch the criminal."
Fang Rui felt that Sun Guangtian was under a lot of pressure, possibly because the case had been unsolved for over half a year, so he was eager to catch the killer.
"I don't need your comfort!" Sun Guangtian cut off Fang Rui's words, "You think this lead is dead? No, I think that vehicle is definitely suspicious. I suspect someone is using Zhang Guofeng to avoid surveillance cameras. They must know Zhang Guofeng. If we keep investigating, we'll definitely find a clue!"
"..."
He discovered that after Zhang Guofeng left home, a man wearing a helmet followed him on an electric bike. The man was young, wearing sportswear, looking like a college student. Near the school, he took off his helmet, and the surveillance camera captured his face.
There were often college students riding electric bikes around the school area, so initially, Sun Guangtian didn't notice anything unusual about this person.
This man was Zhang Guofeng's son, Zhang Ming, 31 years old, working as an animal trainer at a nearby zoo.
He originally worked at a zoo in Linzhou, but suddenly quit and returned to Jiangzhou City a year ago. The zoo where he worked in Linzhou was also close to the wasteland where the bodies were buried.
Sun Guangtian felt that this person should be the killer.
However, he currently had no evidence of Zhang Ming's crimes, so he didn't bring him to the police station for questioning. Instead, he assigned an experienced detective to follow him to prevent him from committing another crime.
Sun Guangtian sent people to investigate the zoo in Linzhou to see if they could find any clues; he himself went to Zhang Guofeng's home while Zhang Ming was at work to search their house.
He examined Zhang Ming's shoes one by one and found that one pair of sneakers had a faint purple stain on the white sole. The shoes had been washed very clean, with no visible dirt, which made the purple stain stand out.
This could very likely be the color that stained his shoes when he stepped on purple fruits in that forest.
"Boss, Sun Guangtian has found another suspect," Zhang updated with the latest information, "He's the son of that sanitation worker, Zhang Ming. Sun Guangtian suspects that the son used his father to transport the bodies, then secretly took the vehicle to bury the bodies while his father was having his affair."
Fang Rui inquired about the situation from Song Haiyang again. Fang Rui felt that although Zhang Ming was very suspicious, his education level was low. How could he design an experiment to collect brain wave data? And how did he obtain the brain wave equipment?
"It seems Zhou Junwei might not be the killer after all!" Zhang sighed, "Could our investigation approach be wrong?"
Mu Mian said, "Maybe the person who designed the experiment and the person who carried it out are not the same? When we conduct experiments, we need assistants. It's very difficult for one person to complete a complex experiment."
"Dr. Mu, since the killer targets couples, he should be single, right? Otherwise, how would he become psychologically twisted due to hating couples?" Zhang asked.
Li chimed in, "That's right, if he had a partner, he probably wouldn't be psychologically disturbed."
"Could we be trapped in a psychological blind spot? Zhang, do you remember you once said that Zhou Junwei might be gay? He and Zhang Ming left Linzhou and returned to Jiangzhou City almost at the same time. Could they be a couple?"
If it was a couple committing the crimes together, everything would make sense.
"Boss, but Zhang Ming works at a zoo, and Zhou Junwei is a university professor. How could these two completely different people be a couple? The gap in their social status is too big."
Fang Rui thought for a moment and said, "They're about the same age. Could they have been middle school or high school classmates?"
Fang Rui and Zhang went to investigate at Zhou Junwei's high school. Zhou Junwei was in Jiangzhou City
Teacher Chen was a man in his fifties, looking very stern and serious. When mentioning Zhou Junwei, his face showed an expression of disgust.
"I have a deep impression of Zhou Junwei as a student. His academic performance was good, but he had psychological problems, a bit perverted. He often harassed their class monitor Chen Yuan'an, and even tried to molest him once."
