Gao Mingqiang was referring to the woman who had previously kidnapped a child, but this incident was clearly more serious. It was unclear what the perpetrator's motive was, and the investigation had yielded no clues.
Xiahou opened a tablet and displayed an image. "If the problem truly lies with the school, then the principal and those teachers are all suspects. We've been conducting in-depth investigations, interviewing these individuals, and visiting their families and friends. We discovered that a teacher named Cao Han had contact with several of the victims prior to their deaths. These are surveillance images from near his home."
"Oh? They all went to his place before the incidents? Then this teacher must be involved!" Liu Yuning exclaimed.
"That's what I thought too. However, when we questioned him several times, he calmly responded that they were just there for tutoring."
"That despicable fellow must be faking it. Does he have an alibi?"
"No, we haven't found any trace of him at the crime scenes."
While Liu Yuning and Xiahou discussed the case, I meticulously compared the photographs from the crime scenes, while also examining the photo of Teacher Cao Han. He appeared burly, with a stubbled face and vacant eyes, not at all like a teacher.
Everyone else had the same impression when looking at his photo. He Xin, sitting beside me, even said, "Holy crap! Someone like this can be a teacher? Then I could be a principal!"
"Don't spout nonsense. Can you judge everything by appearances?" I reprimanded, my gaze never leaving the photos. Perhaps it was luck, but I noticed that while the crime scenes were vastly different, a faint purplish-yellow, trapezoidal light could be seen in the southwest corner of each.
Noticing my silence and intense focus on the photos, Xiao Yuande suddenly asked, "Team leader, have you discovered something?"
"Did you guys notice? Here, and here, and here. The same trapezoidal light appears from the same angle in all these photos."
I pointed to the photos with my index finger, shaking my head as I analyzed them with everyone.
Liu Yuning was the first to notice something. "Indeed, this light is quite strange. Is that a handprint in the middle?"
I replied, "Yes, it looks like someone was rotating their hand, performing a shadow play using the light! Look at the first crime scene, what does that resemble? Doesn't it look like a dog? The second is a fox, and then there's a falcon!"
"That's right, but why would he leave these shadow play imprints at the scene? Wouldn't that expose himself?" He Xin asked doubtfully.
I was also pondering this question. Logically, a criminal wouldn't do this, unless they intended to.
But what was the significance of these shadows? On the surface, their commonality was that they were all animals. The size of the shadows was that of an adult's palm. If there wasn't a lack of video footage, we could even see him performing the actions.
"At most, we can only analyze the type of person this palm belongs to, based on their height and weight. We can't determine anything else!" He Xin stated. I asked her to try and match it first, and we could worry about the rest later.
The meeting concluded, and everyone was temporarily at a loss for how to proceed with the investigation. We could only return to the office.
I was quite troubled myself. However, since I knew Teacher Cao Han was suspicious, I had a reason to question him. I needed to compare his handprint.
I approached Gao Mingqiang, and as soon as I mentioned Cao Han, he understood my intention.
We went to Cao Han's residence again. It was a teacher's residential complex, built through a group purchase for teachers.
Seeing the police again, Cao Han showed no signs of tension and warmly welcomed us inside.
"Two police officers, please be quick with your inquiries. Our school is about to open, and I won't have much time later."
"No rush, Teacher Cao. We've discovered some clues and hope to verify them with you again. Is that alright?" I said.
"Of course, it's my great honor to assist the police!" Cao Han appeared very relaxed and maintained a scholarly demeanor.
It was hard to imagine that someone who looked so rough could possess such refinement, truly embodying the saying: you can't judge a book by its cover.
He shook my hand and then said, "Officer He, this is my first time seeing you. Aren't you that..."
"No, you're mistaken. I'm not him, I just resemble him a bit," I immediately denied.
"Oh, I see. Then what would you like to ask?"
I didn't want to directly compare his handprint, as that would make him suspicious. I asked Gao Mingqiang to question him, then went to his room. He didn't stop me. I took out a shadowless reflection tube and scanned the walls of his room. Finally, on his desk, I found several handprints and fingerprints, all belonging to Cao Han.
I took photos and collected them with adhesive. Then we left.
I told Cao Han, "I've finished my inspection. We can leave now."
"Feel free to come back anytime you need us again!" Cao Han surprisingly said.
"Certainly, Teacher Cao. It's rare to find someone as hospitable as you these days!" Gao Mingqiang added deliberately.
After we got into the car, Gao Mingqiang said, "You inspected his room like that. He must know we suspect him. Aren't you afraid he'll escape?"
"I've arranged for people to stake out near his home. Don't worry. If this guy dares to escape, it would only further prove his guilt. All he can do now is remain calm, just as you saw his reaction earlier."
"Yes, he seemed overly calm. But that makes him even more suspicious."
We chatted as we returned to the Public Security Bureau and tested the evidence with a portable fuming kit for latent prints. The forensics team quickly responded, informing us that the handprints did not belong to the same person.
I had already anticipated this result. Otherwise, we could have apprehended him immediately.
I didn't believe Cao Han was that foolish to leave his own traces at the crime scene. If he were that kind of person, he wouldn't have remained so calm.
Liu Yuning decided to collect the handprints of all the teachers and Principal Guo for comparison. After much effort, none of them matched. The police had deployed a considerable number of personnel, and when the teachers and Principal Guo realized they were suspects, they were furious, accusing us of baseless investigations.
She said to me in disappointment, "How could this be? Have we gone in the wrong direction? How could this happen? We've wasted so much time!"