Guan Li looked at the front and back doors, and the police officers who were strictly guarded at the windows, and breathed a sigh of relief.

"Do you remember what that schoolgirl looked like?"

The police officer thought about it and left Guan Li with a general description.

Guan Li felt that it was a bit similar to Xiao Rui who was vague in the surveillance.

He took Zuo Ling into the large classroom, where landmarks were still painted on the floor and desk, and the original blood stains had turned dark red.

Guan Li looked up at the top of the lectern, it was a central air conditioning pipe, and he couldn't see anything abnormal.

He ordered a ladder to be found, and he climbed it.

When he was about the same as the pipe, he saw a thin red mark on the white pipe.

He wiped it with a cotton swab and put it in the evidence bag, and stared at the strangulation marks on the pipe for a long time.

Then he looked in this direction at the location where Zhao Yue'an had passed out.

Strangulation, white light, straight bloodstains, in an instant, he understood the murderer's modus operandi.

"Zuo Ling, help me do an experiment."

With that, he walked down and asked the officer to prepare things and put them on top of the pipe in his way.

Then put a watermelon on the lectern and looked at the location, Guan Li nodded at Zuo Ling.

Zuo Ling pressed the switch in his hand, and a silver point of light flashed instantly, and it was inserted straight into the watermelon.

Then after turning on the central air conditioner, a white light flew out of the watermelon quickly and disappeared into the sky.

Guan Li understands this, but how does the situation on Zhao Yuean's side operate?

He paced back and forth in front of the podium, stopping at the very center of the podium as he walked.

He crouched down and looked at the multimedia box, and slowly opened it.

Inside the box are the intricate wiring of multimedia projectors, but there is a small space that can fully accommodate one person.

Guan Li and Zuo Lingzai carefully examined the multimedia box, and finally found a trace of blood in the gap.

If it was really Zhao Yue'an who killed him, the bloodstains should only exist on the outside of the multimedia box.

However, blood was seen in the internal cracks, proving that someone had rubbed the blood into the interior at that time.

"The modus operandi is almost clear, but the key evidence...

Guan Li was talking when he suddenly received a call from Jia Fan.

"Boss, I found it. There were traces of thin thread binding on the dagger, and in the exhaust outlet of the central air conditioner, a roll of fishing line was found, with a slender silver needle on it. ”

"Well, hard work."

After hanging up the phone, Guan Li's heart was somewhat relieved, and now as long as the evidence of the murderer's crime can be found, everything can be closed.

At this moment, Xiao Fan sent a video.

After Guan Li clicked on it, he found that it was a surveillance video, but this video had not appeared before.

"Boss, this video has been cut, but you're still good."

The corners of Guan Li's mouth hooked, and he replied with a sneer.

"Keep all the evidence, keep him under control, and bring the relevant people to the school."

Half an hour later, the relevant leaders of North University of China and the police came to the large classroom, including Zhao Yuean.

Guan Li glanced at her and gave her a reassuring look.

"Yesterday, Professor Yan was killed, and only the suspect Zhao Yuean was present at the time. Today, I will restore the modus operandi and process of the case. ”

After speaking, Zuo Ling took out the watermelon and put it on the lectern under Guan Li's signal.

At this time, there were many students standing outside the door, all wanting to see how Guan Li solved this case and whether he would really convict Zhao Yuean.

"First of all, after a forensic investigation, the real cause of Professor Yan's death was not a ruptured lung, but brain death.

Here is the forensic autopsy report to testify.

Secondly, there is something very important missing in the whole case, which is the monitoring of the school. ”

The logistics director hurriedly said: "In addition to the toilets and dormitories, there are monitors in every public corner of the school. ”

The logistics director was afraid that he would not be able to find out the case and blame him.

Guan Li nodded to calm him down, and continued: "There is one in the monitoring room, but the monitoring has been manipulated.

Fortunately, the criminal investigation team has technicians who have repaired it. Let's take a look at the modus operandi first. ”

After speaking, Guan Li did the techniques of the previous test, and then put the physical evidence on the table one by one.

"These are all physical evidence found during the investigation, and they are all collected and reviewed by relevant personnel.

So far, it can only prove that Professor Yan's death is a bit confusing, but it cannot prove Zhao Yuean's innocence. ”

The students who were originally going to shout for Guan Li to secretly change their concepts to shield Zhao Yuean were forced to hold back by Guan Li's words.

He took a deep look at Xiao Rui in the group of students, and Xiao Rui's face was a little pale at this time.

"But there is no way to design Professor Yan's brain death and stab him with a dagger, so you need help.

If Zhao Yuean is the murderer, there is no need to be so troublesome, just choose one of them, and brain death is easier to succeed without being discovered.

Why did she make such a move and make herself suspicious? ”

Speaking of which, many people understand, and most people are also on Zhao Yuean's side, thinking that she may really be framed.

But there are still some people who just feel that Guan Li is shielding her.

"What if she's not the murderer? Who is the murderer? You can't say that Zhao Yuean is not a murderer, and Professor Yan will die in vain, right? ”

"That's right! As a police officer, do you want to shield the murderer? ”

"It's really a bad day, there is a captain as a boyfriend, and even people dare to kill people...

Looking at the few people who were obviously rhythmic, Guan Li looked at them with a smile.

"How many of you, which department are you from? Who is the class tutor? ”

Those people were obviously stunned, their eyes were a little evasive, but they still stiffened their necks and replied: "Don't you want to threaten us!" Since you want to investigate the case, you have to give Professor Yan justice! ”

Guan Li nodded, "That's right, but none of you are students in this school, how can you know so clearly?" And how did you get into school? ”

"Who told you we're not..."

Before the man could finish speaking, he was grabbed by the sleeve.

At this time, he realized that the people around him were far away from them, because there were all the majors present, but no one had seen them.

"Even if you want to find a trust, you can find someone who is smarter, right? So stupid, isn't it self-confessing? ”

After speaking, Guan Li looked at Xiao Rui behind them.

"Captain Guan, what do you mean by looking at me like this? Do you suspect that I killed Professor Yan? ”

Xiao Rui's face was shocked with grievances, and the surrounding students were also full of doubts.

"You're trying to say you weren't there at the time of the crime, right?"

Xiao Rui held the psychological book and nodded innocently.

"That's right! At the time of the crime, I was preparing to take a medical class, and I was in the medical building opposite, which is far away from here. ”

Xiao Rui said it rightly, she had an alibi, even if Guan Li knew the modus operandi, he couldn't do anything to her.