Chapter 52: Criminal Investigation World (2)

Lin Yuetian drove to the police station for the task force meeting. The system had plenty to say about this scene, throwing out comments like “a weasel wishing a hen a Happy New Year.” Lin Yuetian figured its grasp of idioms wasn’t all that impressive either.

The task force leader, Chen Chen, had been waiting for him for quite a while. Chen Chen was forty years old this year and had worked with the original host multiple times in the past—they could be considered friends. He had heard about the mess Lin Yuetian had recently gotten into, so the first thing he did was pat him on the shoulder. “Having pressure is a good thing, but Xiao Lin, don’t let it weigh you down too much.”

“I’m fine, Captain Chen.” Lin Yuetian pulled out a chair and sat down, taking out the case files and his notebook. “Let’s begin, Captain.”

Chen Chen nodded and addressed the other officers. “Alright, this is the tenth task force meeting on the 4/27 Blunt Force Serial Murders. Let’s officially begin.”

He tapped his computer, projecting a PowerPoint presentation onto the screen as he reviewed the case:

“The first victim in the 4/27 Serial Murders was Zhao Fanyun, a freelancer who lived alone. The crime occurred on April 27. The victim had a habit of going for morning runs and left home at 5 AM for a jog around the neighborhood. At 5:20, he went outside the community to buy breakfast. Then, at 5:40, he took a shortcut through this alley on his way home, where he encountered the killer. The perpetrator struck him on the head with a blunt object, killing him instantly. His body was discovered by a sanitation worker at noon. The autopsy determined that the murder weapon was likely a claw hammer.

We investigated all the hardware stores in the city but found no suspicious individuals who had purchased a claw hammer in the three months leading up to the crime. There were no footprints, fingerprints, DNA, or hair left at the scene. The victim lived in a remote area, and the alley was rarely used, so no witnesses were found.”

The PowerPoint switched to the second slide.

Chen Chen continued, “From the second victim onward, the perpetrator began targeting victims on rainy nights. The second victim, He Dan, was in the clothing business and had a complex social network. He was also an avid fisherman and often fished at a reservoir.

On the night of his murder, He Dan called his wife at 8 PM—two hours before the crime. He mentioned that it had started raining, but he had a raincoat and planned to continue fishing since he hadn’t caught anything all day. When he didn’t return home that night, his wife reported him missing the next day, and his body was found soon after. Like the first victim, he suffered blunt force trauma, but this time, the weapon was a rock from near the reservoir.

Take a look at this slide—the weapon was recovered, but there were no usable traces on it. Due to the heavy rain, the crime scene was severely compromised.”

Chen Chen moved on. “The subsequent victims included both men and women. We thoroughly examined the social connections of all five victims but found no common links or individuals with clear motives to kill them. The only commonality is the lack of evidence left at the crime scenes. All five victims were killed with blunt objects, but forensic analysis showed that for the last three, the murder weapon was likely a stonemason’s hammer.

However, this doesn’t necessarily mean the killer is a construction worker. Our city’s construction sites don’t have strict tool management, so theft is a possibility. Our profiler, Xiao Xie, has put together a criminal profile, which I’ve printed out for everyone to review.”

Chen Chen handed out a stack of printed reports. Lin Yuetian took one and began reading. The contents were concise:

Male, young to middle-aged (estimated 20–45 years old)

Highly skilled at evading detection, possibly has a criminal record

Random victim selection, antisocial tendencies

May have a specific psychological attachment to rain or blunt weapons

Chen Chen turned to Lin Yuetian, who had remained silent throughout the discussion. “Detective Lin, any thoughts?”

Lin Yuetian repeated a key detail from the profile. “The perpetrator is highly skilled at avoiding detection. I think he might have a prior criminal record.”

“We thought of that already,” Chen Chen said, exasperated. “We investigated all blunt force assault and homicide cases in this city and three neighboring ones over the past two years. Every identified perpetrator is either already caught and in prison or otherwise incapable of committing these crimes. We even checked their close relatives but found no one with the opportunity to commit all five murders.”

“That’s not what I mean,” Lin Yuetian clarified. “Why do you think the killer chooses rainy nights?”

“To hide evidence,” Chen Chen answered.

“Yes, but there’s another factor.” Lin Yuetian pointed at the case files. “The first victim—Zhao Fanyun, the one killed in the alley—wasn’t murdered on a rainy night, right? He was killed in the early morning, while out for a run.”

“Early morning still helps conceal evidence. Fewer people around, less chance of witnesses.”

“That’s true, but here’s the question: why did the killer initially choose the early morning but then switch to rainy nights?” Lin Yuetian mused. “I put myself in his shoes and figured—rainy nights are just more convenient. And what’s the most convenient thing about rain? Rain washes things away—especially blood.”

“Why blood?” The system spoke in a tone that suggested it couldn’t comprehend the minds of psychopaths.

“Because some people wear raincoats in the rain,” Lin Yuetian explained to Chen Chen—and, indirectly, to the system. “In murder cases, blood evidence is one of the hardest things to deal with. The most difficult blood evidence isn’t necessarily at the crime scene but on the killer himself.

How can a murderer leave a crime scene without looking suspicious and without any traces of blood on them? The answer: a raincoat.

The killer most likely wears a rubber raincoat while committing the murders. Afterward, the rain naturally washes away any blood on the coat. If a passerby sees someone walking away in a raincoat during a downpour, they won’t think twice about it. I suspect that the perpetrator initially chose early mornings because he thought it was safer—fewer witnesses and more time to change clothes. But in reality, changing clothes is a hassle, especially since blood can get on pants too—”

“No need to get that graphic.” The system coughed in protest.

Lin Yuetian cleared his throat. “In any case, he likely found his original method too inconvenient and risky after the first murder, so he switched to rainy nights to minimize exposure.”

He added, “Besides that, the murder weapon used in each crime was different, though they were all blunt instruments… The first time, it was a claw hammer; the second time, the perpetrator picked up a stone at the scene; and only after the third crime did they settle on using a stonemason’s hammer. This suggests they were searching for the most suitable weapon.”

Chen Chen nodded and continued asking, “That’s true, but why is this important? If the weapon feels awkward to use, naturally, they’d switch to a better one.”

“It’s very important,” Lin Yuetian said. “First, it shows that the perpetrator is refining their methods with each crime. This might be their first time killing.”

“Doesn’t that contradict your earlier claim that they have a criminal record?” someone else asked in confusion.

“It doesn’t,” Lin Yuetian paused. “What I mean is… was Zhao Fanyun, the first victim, really the perpetrator’s first kill in this series?”

“?”

Lin Yuetian continued, “I’ve been wondering why the perpetrator chose a blunt weapon… Of course, blunt weapons are often more practical—they’re lethal, easier to use, and unlike knives, they’re not regulated. With non-restricted knives, like small blades, it actually takes a lot of skill to kill someone quickly or at least incapacitate them before they can call for help or fight back…”

“Only someone like you, an elite in your field, could pull that off, right?” The system guessed at his meaning.

“You’re quite perceptive.” Lin Yuetian responded in his mind with satisfaction.

Naturally, he wouldn’t say that out loud. Instead, he continued his analysis: “But undeniably, if my theory is correct and the perpetrator has no prior record, then this is very strange. For someone without a criminal record, their first thought when considering murder would typically be to use a blade, right? A fruit knife, a screwdriver, something like that. So why did the perpetrator think of using a blunt weapon?”

“Why?” Chen Chen, engrossed in the discussion, couldn’t help but ask.

“My bold guess,” Lin Yuetian said, “is that there was another victim before this case even started—someone who likely died from stab wounds, possibly multiple stabs leading to excessive blood loss. I suspect the perpetrator tried using a bladed weapon once but found it ineffective, which led them to switch to a blunt instrument. That’s why I said they have a criminal record.”

Lin Yuetian concluded, “That’s why I believe we should investigate all unsolved stabbing murders in this city from the past six months, then reassess and merge any relevant cases with our current investigation.”