The two-story building where Cheng Yuguo's family lives is not large, the first floor is the living room, kitchen, and bathroom, and the second floor is two bedrooms plus a balcony and a bathroom.

may be because Cheng Yuguo himself is lazy, and the family's life is not satisfactory, Xiao Ran took a look upstairs and downstairs and found that the cleaning in Cheng Yuguo was not very clean.

There are some places that can be passed, as long as no one can see them, they can not be cleaned without cleaning.

The same is true in the bathroom on the first floor.

The corners of the bathroom floor were covered with black-brown stains, the washbasin was very dirty, the faucets and mirrors were covered with dried water stains and toothpaste marks, and the white toilet seat had turned yellow-brown.

Obviously, Cheng Yuguo's family has not cleaned this bathroom for a long time.

According to the photos taken by the on-site investigators at the time, it can be seen that at the time of the crime, there were still various hairs of different lengths scattered in the bathroom, but those hairs were taken away for inspection.

However, the final test results showed that the hairs belonged to Cheng Yuguo's family, and no other people's DNA was detected.

What attracted Xiao Ran's attention was not the environment in the bathroom, but the toilet that was covered.

There is nothing to attract attention to this toilet, and it is very old and dirty, especially inconspicuous, but looking at the relatively clean area at the front end of the toilet lid because it is often lifted, Xiao Ran had an idea in his heart.

called Zhang Lei and Yu Mengqing over, and the three of them nested in this small bathroom, and the atmosphere was inevitably a little awkward.

"What's the situation, have you found it?" As soon as Zhang Lei came in, he took the ultraviolet flashlight and kept scanning, but he didn't see any reason.

Xiao Ran looked at the scene investigation report at the time of the crime and asked Yu Mengqing: "On this toilet, no fingerprints were extracted at that time, right?"

"Huh?"

Yu Mengqing was stunned, very puzzled why Xiao Ran would pay attention to such an ordinary toilet, could it be that the thinking of criminal investigation experts is like this, so weird and strange?

However, as a person who often sorts out and summarizes the progress content of all parties, Yu Mengqing basically has an impression of the content on the investigation report.

She thought for a moment, then shook her head and said, "Not on the toilet." However, the faucet grip and the toiletries here were found, but those were later proved to be traces of the life of Cheng Yuguo's family. ”

Xiao Ran nodded, put on gloves and asked Zhang Lei for the tape, and tore off a piece of tape that was attached to the front of the toilet seat.

Zhang Lei also squatted down and came over, watching Xiao Ran tear off the tape, and sure enough, he didn't find any fingerprint traces, and couldn't help asking, "Xiao Ran, what are you doing?"

Xiao Ran raised the corners of his mouth and said to Zhang Lei: "Assuming this is your toilet, you now simulate the whole process of going to the toilet." ”

"Simulate going to the toilet?—— big brother, it's not that you can't go to the toilet, who doesn't have those steps, and you still use me to simulate?"

Zhang Lei said, lifted the toilet lid, sat up for a while, and wanted to press the water tank button, but was stopped by Xiao Ran, and then casually closed the toilet lid: "Isn't it all like this?"

Xiao Ran didn't open his mouth, but just tore two more pieces of tape, one on the button of the water tank, which was relatively clean because of frequent use, and the other on the position where Zhang Lei put it down with his fingers on the toilet lid.

Although Xiao Ran has not said it explicitly, compared to Yu Mengqing, who is still in a state of blindfolding, Zhang Lei quickly came back to his senses.

He removed two pieces of tape, and there was nothing on the tape on the water tank button, but on the other tape, two Zhang Lei's mutilated fingerprints appeared.

Of course, if Zhang Lei really pressed the water tank button just now, there would definitely be his fingerprints on the other piece of tape.

Looking at the two tapes on their hands, Zhang Lei and Xiao Ran glanced at each other, "Is that so?"

Xiao Ran nodded.

"What is it? Hey, what the hell is it? I'm almost confused by you!" Yu Mengqing looked left and right, and really couldn't understand what medicine Xiao Ran and Zhang Lei were selling in the gourd.

Zhang Lei shook the tape in front of Yu Mengqing's eyes and asked, "What's on the tape?"

"Your fingerprints. ”

"Then why didn't there be fingerprints left on the toilet at that time?"

Yu Mengqing was slightly stunned and replied, "How do I know...... Maybe they wiped it off after going to the toilet. ”

"When you go to the toilet, you wipe the toilet lid and buttons?"

Zhang Lei looked at Yu Mengqing in surprise, and pointed to those dirty traces: "And look at this bathroom, and the toilet is dirty like this, do you think Cheng Yuguo's family will wipe the fingerprints and touch marks on the toilet after going to the toilet?"

“......”

After Yu Mengqing was silent for a while, she finally came back to her senses and exclaimed, "So you mean, the murderer used this toilet at that time?!"

"I guess so. ”

Xiao Ran didn't answer surely, he took a strong flashlight, squatted by the toilet, and carefully observed the situation in the toilet.

I have to say that because it has not been cleaned for a long time, this toilet is dirty, not only the toilet seat has turned bright yellow, but even the toilet bowl is full of a large number of yellow and brown dot marks.

Seeing Xiao Ran lying on the toilet with a flashlight, her whole face almost reaching the water seal, although Yu Mengqing felt disgusting in her heart, she also had a strong sense of peacekeeping.

Sure enough, it is not so easy to become a criminal investigation expert, you have to do everything, and the kind of picture in the TV series that can be seen and understood is impossible at all.

Although the appearance of the person in front of him is as good as those idol stars, isn't he still holding a plastic rod and stirring the toilet bowl with all kinds of excrement remaining?

"There seems to be some food residue left in the water seal, let's remove this toilet, be careful not to tilt the water inside. ”

Xiao Ran observed for a while, asked Yu Mengqing to turn on the flashlight, and then worked with Zhang Lei to dismantle the toilet.

Yu Mengqing bent over, looked at the two who were busy with their work, and couldn't help asking, "Why is it food scraps?" The excrement was blistered and not rinsed, so it looks like food scraps, right?"

Xiao Ran and Zhang Lei paused at the same time, and only said in a half-loud voice, "I hope not." ”

After some tossing, the remaining water seal in the toilet bowl, as well as the debris in it, were put into the ziplock bag.

Zhang Lei held the ziplock bag in one hand, observed the substances in the water with the light in the other, and analyzed uncertainly: "It shouldn't be excrement, it seems to be food residue from vomit." ”

"It won't be when the murderer commits the crime...... Did you vomit nauseously?"

Yu Mengqing was surprised, "How is this possible, such a cruel suspect, just like in foreign movies, treats killing people as art, how can he vomit?"

"It doesn't matter if he vomits or not, just send it to the technical center for testing. Zhang Lei said.

Yu Mengqing shook her head and asked again: "But if this is really vomit residue, it has been soaked in this water for almost half a month, can DNA still be extracted?"

"Give it a try. Xiao Ran was also unsure.

But if the murderer was really disgusted by his behavior in the process of committing the crime at that time, what was the psychological environment of the murderer at that time?