After Xu Tian released cruel words, the room instantly fell into a dead silence, the snowstorm outside continued, when the room became silent, the old door was squeaked by the wind, the cold wind through the crack in the door broke through the slight heat in the room, Xu Tian tightened his clothes, walked to the door and opened the door.

"What are you doing? If it's too hot, go out. Chen Po wrapped her cotton coat tightly and accused Xu Tiandao.

"I'm sorry, if you want to find out the murderer, you can only see who is more hardy." Xu Tian said.

"Are you crazy......" Before Chen Po could finish speaking, her eyes suddenly became frightened, staring directly at the snow outside the door.

Xu Tian suddenly felt a shudder, and when he looked back, a row of huge footprints appeared on the snow, and the shape of this row of footprints was very familiar, it was the row of dog god footprints that Xu Tian saw in Lao Hei's house in Lijia Village.

"It's the dog god...... Just now, the evil wind was the dog god looking at us through the crack in the door, so I said why there was a cold wind blowing in through the crack in the door, it was the dog god breathing. Chen Po looked at the row of footprints outside the door and said in horror.

Xu Tian glanced at Teacher Jin and motioned for Teacher Jin to stay in the house, and then Xu Tian chased him out.

The row of footprints outside leads to the Yong Road, and disappears when they reach the end of the road, judging from the shape of the footprints, each footprint is about 80 centimeters in diameter and about 10 centimeters in depth.

What's going on with this row of footprints? Everyone had entered the guest room together before, Xu Tian had always stayed with everyone, and absolutely no one had ever gone out.

What does this mean? Is it telling everyone that the murderer is the dog god? Just now, only Chen Po was shouting, and it is not an exaggeration for an old man of Chen Po's age to believe in superstitious things such as dog gods, but what about other people?

Obviously, Dongzi and Chen Fan didn't believe it, and Yang Qi was even more disdainful of these footprints, so what the murderer wanted to express was also obvious, that is, to tell everyone that the murderer was an outsider.

The university was falling very violently, and in the time that Xu Tian was thinking about it, half of the huge footprints in the snow had been buried.

That means that these footprints were stepped on just now, and there should have been someone outside just now, Chen Po was right, but Xu Tian didn't believe in such a thing as a dog god.

There were no footprints around the huge footprints, and they were broken so neatly that it was as if the dog god had disappeared out of thin air after walking from the door of the guest room.

Xu Tian did not forget to take pictures when observing these footprints, and after investigating the surroundings of the footprints, Xu Tian returned to the guest room.

"Mr. Jin, you see, the design of these footprints is actually very rough." Xu Tian said.

"That's right, it's very clean between each footprint, if it's the footprints stepped on by the dog god, then it is impossible for there to be no scratches between the footprints and the footprints, just like when we walk on the snow with deep snow, there will definitely be a few footprints between the traces of being scratched by shoes, because no one can guarantee that every step will be lifted high, whether it is a person or an animal, there may be times when the feet are not pulled high." Teacher Jin analyzed.

"But how did this row of huge footprints come about? I didn't hear anything other than the wind blowing outside, and if there were people outside, we wouldn't have noticed it at all, because the door to this room was one of those very old wooden doors, and the crack was so large that if someone was dangling outside, we would have noticed a figure swaying outside. Xu Tian said.

"I think these footprints are more mechanical, and the footprints are too regular with the footprints, like the footprints of a person with obsessive-compulsive disorder." Teacher Jin said.

"What do you say? Obsessive-compulsive disorder? Xu Tian suddenly realized.

"Did you think of anything?" Teacher Jin asked.

"That's right, obsessive-compulsive disorder, this serial murderer has a very serious obsessive-compulsive disorder, I finally understand." Xu Tian said.

"Why didn't I see that?" Teacher Jin said.

"First of all, Danxin's corpse, when we found Danxin's body, there were two steel bars inserted in Danxin's chest, although I don't know medical skills, but the two steel bars inserted into Danxin's chest are both lungs, there is no doubt about this, right?" Xu Tian said.

"That's right." Teacher Jin said.

"Then there was Mr. Fang, I noticed that there was blood flowing from the corners of Mr. Fang's mouth when he died, and I could see very clearly that there was blood flowing from the corners of Mr. Fang's mouth at that time. Then there is Jiaojiao, and when we find Jiaojiao's body hanging from the door of the study, Jiaojiao's body is swaying regularly from side to side. Then there was Li Nana's body, and when I found Li Nana's head in the kitchen, the blood on the kitchen floor was very symmetrical, which I only remember now. Xu Tian said, and took out his mobile phone and flipped out the photo of the blood on the kitchen floor to show Mr. Jin.

"You're right, what about the charred corpse in the boiler?" Teacher Jin asked.

"I haven't thought of any symmetry at the moment, let's carefully look through the photos of the crime scene." Xu Tian said.

Xu Tian carefully compared every photo in the boiler room, but he didn't find any symmetry in that photo.

"Am I mistaken? Impossible! Xu Tian said while flipping through the photos.

"First of all, what does the symmetry of each corpse reveal, and what does it have to do with the case?" Teacher Jin asked.

"If the murderer is a person with obsessive-compulsive disorder, then the murderer must do something very neurotic." Xu Tian said.

"For example?" Teacher Jin asked.

"If the murderer is a person with a very serious obsessive-compulsive disorder, then the murderer will definitely leave a horse foot, such as a blood spot that collapses on the murderer's body, if the murderer does not have time to wipe off the blood spot, then it is likely to make another symmetrical blood spot." Xu Tian said.

"I thought you had deduced some important clues! That's it? Teacher Jin said with a little disappointment.

"Don't believe my reasoning, crime is a very subtle thing, each corpse has a symmetrical point, then the murderer will definitely continue this style and continue to commit crimes." Xu Tian said.

"I said you, don't you know if you look at Xiao Ai's corpse!" Yang Qi said.

Xu Tian and Teacher Jin were suddenly startled, and the two seemed to be in a very embarrassing situation.

"Hahaha...... They can't find the point of symmetry from Xiao Ai. Dongzi said with a laugh on the side.

"It's you, it's you, Dongzi, you're the one who started it all." Xu Tian rushed to Xiao Ai's side and said to the protector Xiao Ai.