Yu Fan's firm tone and eyes seemed to have seen through the truth of everything.

But Chen Jieyang was still blinded by this operation: "Old Yu, what's going on?" ”

Yu Fan said calmly: "This red one is not blood water at all, but ferric chloride." I put the tea leaves in the bottle, and the tannic acid in the tea leaves reacted with the ferric iron ions to form black ferric tanninate. Then I added oxalic acid to reduce the black color, which supported my inference. ”

Chen Jieyang asked again: "That's very strange, where does so much ferric chloride come from in this river?" There is no industrial park and no chemical plant in this area, so how can there be so many polluting emissions? ”

Yu Fan: "Your question is good, the source may not be the place where the water is polluted, the source is the place where the water is purified!" ”

Chen Jiaoyang: "Why am I being more and more confused by you?" ”

Yu Fan closed his eyes and entered a state of flow, and a map of the neighborhood appeared in his mind. The map gradually becomes clearer, enlarged, and larger in the world of the mind.

Suddenly, Yu Fan opened his eyes! "This is it, the sewage treatment plant!" Yu Fan said categorically.

Yu Fan got up and walked next to the white-haired old man, these old villagers had been watching them from the side, hoping that their investigation would find out the truth and restore peace to Beiqiaogou, otherwise they would be terrified all day long.

Yu Fan opened his mouth and told the old man: "Old man, don't worry, I have already done a simple test just now, this red water is not blood water at all, and there is no superstitious thing like 'blood sacrifice', please rest assured." ”

An old man next to him, a slightly younger man, stepped forward, with a half-believing expression, and asked in an authentic dialect, "This little expert, what is this?" ”

Yu Fan didn't answer directly, but asked the villagers: "Folks, is there a sewage treatment plant near you?" ”

Everyone nodded, and an old woman in pink pointed to the distance and said, "That's the direction, just walk all the way back to the main road, not far." ”

Yu Fan smiled with satisfaction: "That's right!" I strongly suspect that this red chemical came out of the sewage treatment plant! ”

Chen Jieyang nodded as if he didn't understand and said, "You mean that the sewage treatment plant discharged the water before it was cleaned?" ”

The corners of Yu Fan's mouth rose, revealing a confident smile, and said, "Maybe it's too clean." ”

Chen Xiangyang was stunned again, he vaguely felt that this should be a problem related to chemistry, otherwise Yu Fan would not be so confident, but when he just wanted to ask, he was interrupted by a voice from a distance.

"Found it! Got it! It was Chen Jieyang's colleague, who rushed over with a bag in his hand.

Chen Jieyang showed an excited expression on his face, but he immediately pretended to be calm again: "What did you find?" Helter-skelter. ”

"We found something very strange, some bones were found on the ground in many parts of the village." Chen Xiangyang's colleague said.

Chen Frameyang was a little disappointed after using it: "Eating in the countryside is not like in the city, and it is normal to throw the remaining bones outside for dogs to eat." ”

The colleague then said: "No, these bones have been manipulated, you see, there is a lot of powder stuffed in the middle of these bones, and it is very fragrant, very strange." ”

Yu Fan took the evidence bag, took out the bones and smelled them, and said to himself: "I see, it makes sense now." ”

Chen Jiaoyang patted Yu Fan, "Old Yu, what's going on?" The villagers also showed very curious expressions.

Yu Fan said categorically: "These dogs are not evil at all, they are poisoned!" ”

Chen Jiaoyang was shocked: "You mean poisoning?" This problem is serious! ”

Yu Fan: "That's right, it's just that this poison is only harmful to dogs, but it is safe for the human body." It's all man-made. This bone is stuffed with cocoa powder! The theobromine in cocoa powder can act on the central nervous system and heart muscle of the puppy, thus poisoning the dog. Both humans and cats can digest theobromine through metabolism, but dogs' digestive systems do not. Methylxanthines can stimulate the dog's central nervous system, causing its heart rate to rise sharply, thus causing a variety of poisoning symptoms. The symptoms after eating cocoa powder are hyperactivity and thirst, which is consistent with the strange phenomenon of dogs in the village, this thing only needs a very low dose to kill dogs, chocolate also contains a lot of theobromine, which is why dogs can't eat chocolate! “

Chen Xiangyang said thoughtfully: "This suspect has a lot of means, he doesn't use traditional poisons, avoids people's eyes and ears, and can also prevent harm to human beings and make things bigger, and use this kind of food that can be found everywhere to commit crimes." But what is his purpose? Going out of your way to do this series of pretending to be ghosts, making the village weird, and intimidating us not to continue picketing? ”

Yu Fan didn't answer, and continued to ask the villagers: "Have you seen any strangers coming to the village in the past two days?" ”

Everyone looks at me, I look at you, and they shake their heads. The white-bearded man said, "We were in the village during the day, and we didn't see any strangers coming. We are still relatively sure of this, because our village is small, and there is water on all sides, strangers can only come in from the entrance of the village, and there are usually no strangers in our village, if strangers come, we will definitely find out. ”

Chen Jieyang answered: "In this way, this person came here quietly at night to do tricks. And ......"

Yu Fan continued to pick up the dragon: "And when he came over at night, he brought those bones that were good for his hands and feet to attract the dogs in the village, so that the dogs in the village would not bark and the villagers would not find out." Then he could go to the small courtyard at the end of the village to set up the scene. And after feeding the dog, in the next day or two, the dog can get sick and die one after another, so that there is no superfluous operation. ”

Chen Huanyang: "The small abacus is quite fine. It's cunning. ”

Yu Fan's expression suddenly became solemn, his brows tightened, and he said, "But don't you think it's strange?" The MLM person is not highly educated, how could he come up with these methods? Moreover, when we found their stronghold, the rest of the people should have fled, so why bother to pretend to be ghosts to do this? Is there something they have to cover up? ”

Chen Jieyang also felt strange when he said this, but he turned his mind and said, "Then let's go and ask this ghost in person." ”

Chen Jiayang and Yu Fan looked at each other and nodded, everyone got into the car, the destination, Beiqiaogou Sewage Treatment Plant!

The crow in the tree combed its feathers with its beak and, with a gust of wind, flew away.