After death from hydrogen (cyanide) poisoning, the chemical component will dissolve due to the decay of the body. Now that the remains have turned to bones, it is even more impossible to find the poison.

So, after killing the first woman, did the murderer accidentally come into contact with hydrogen and found that this method was more effective, so he changed his killing methods to drowning?

Xie Qing ordered chicken legs and pickled cabbage, sat down, and thought while eating.

She thought that this possibility was not impossible, but it was only 20% to 30%, and the possibility of death by other means was still not small.

For example, if the murderer was frozen to death, the murderer might suddenly become a cold storage manager; if the murderer had heatstroke, the murderer might suddenly come into contact with sweat steaming; if the murderer died of starvation and bleeding, the murderer had an independent residence that was not discovered by others, and so on.

But if we consider all factors, including superstition, mountain climbing, and the fact that the murderer has achieved success, the possibility of hydrogen poisoning will be greater.

Xie Qing put herself in the murderer's shoes and thought that if she gave up drowning as a means of killing, she must have mastered a simpler method.

Otherwise, it would be more satisfying to watch the enemy slowly die under your iron fist, right?

Xie Qing thought of herself pressing someone's head and stuffing him into the bathtub, and shuddered involuntarily.

I can't think about it anymore.

As a police officer, you must always be mentally alert, otherwise, there is only a fine line between genius and perversion.

After dinner, Xie Qing returned to the dormitory and sat down at the desk, eating melon seeds while recording today's work content.

After finishing writing, she found a book on forensic toxicology, re-read the chapter on hydrides, and called Tan Yi.

"Beep, beep..." The phone was hung up.

This was the first time Xie Qing had been hung up on since she got her mobile phone. She was shocked and quickly ate some melon seeds to suppress her shock.

Eating melon seeds alone was a bit dry, so Xie Qing found some milk powder and made a cup of milk.

It was actually quite comfortable to read a book while eating melon seeds and occasionally drinking a sip of milk.

After finishing a chapter, the phone rang. It was Tan Yi who called.

"Sorry, thank you. The meeting just ended." "It's

okay. I guessed it."

"Well, what's the matter?"

"I suddenly thought of a situation and wanted to report it to Captain Tan."

"Go ahead."

"I think there is a possibility of hydrogen poisoning, such as the murderer working in a gold and silver mine or an electroplating plant, or coming into contact with pest control, rat poison development, and fumigation disinfectants, etc."

"Well..." Tan Yi made an ambiguous sound, and he spoke again after several seconds, "I remember Li Ji mentioned two people at the meeting. They were both related to mining, and he is also a mountaineering enthusiast. That's right, copper mines are likely to be accompanied by gold mines."

"Yes." Xie Qing affirmed, "But I still want to remind Captain Tan that hydride is only one of the possibilities."

Tan Yi's voice had a hint of smile, "Don't worry, I understand. It just so happens that I have something to ask you."

Xie Qing asked, "What is it?"

Tan Yi said, "I received a call from Shen Qing, saying that she asked you and your sister to have dinner together, and asked me and Lao Chai to go too."

Xie Qing didn't expect that he was talking about this matter. After thinking about it, he told the truth, "That's true, but because of the nature of our work, I haven't agreed to her for the time being. But... I might not go if there's nothing to do. If someone asks about it, please help me cover it up."

"Hehe..." Tan Yi laughed softly, "I understand, don't worry."

Xie Qing had never heard such a hearty laugh from Tan Yi, rustling, so pleasant to the ear that it gave people goosebumps.

She wiped away the slightest bit of strangeness in her heart, said goodbye, hung up the phone, and went to the bathroom with a basin of water and a cup of milk.

...

Tan Yi smiled and shook his head. Lao Chai said that Xie Qing was a little fox, but she was also very direct when she needed to be direct.

It depends on who you are talking to!

He made a cup of tea, dug out the information handed over by Li Ji, and soon found two people related to the copper mine.

One was surnamed Wang, Wang Xinyang, 31 years old, from Anhai City.

One was surnamed Che, Che Zhe, 33 years old, from Xiang'an County, and lived in Anhai City.

The two had already started families, but because of their wealthy family background, they had a lot of fun and were said to have affairs with several women at the same time.

However, both of their fathers were still alive and lived a more comfortable life than anyone else.

If the murderer was one of them, all the guesses about the male corpse in the burial ground would be wrong.

Although he was a little superstitious, he still believed that the male corpse and the murderer had a very close relationship.

However...is it possible that it was not the father, but the grandfather?

It seems logical.

Then let's investigate it in detail - although the probability is not high, as long as Xiao Xie is lucky enough, he can get a piece of credit in this serial murder case.

He put this information on it, refilled some hot water, and just sat down when the office phone rang.

Tan Yi picked up the phone.

"Hello, Tan Yi."

"Captain Tan, this is Chu Hua. I hope I am not disturbing you."

"No, no, I'm still in the office. How are you guys doing? Any news?"

"We have matched two remains, but we are not completely sure yet. We may need to do a DNA match."

"Oh, about this matter, I will report it to the bureau tomorrow. When there is more progress, we will report it together."

"That's what I meant. How is the situation in the city? Is there any progress?"

"There are more than 50 suspected people in the city. Because of the long time, it is difficult to identify them in forensic medicine. We are still in the difficult investigation."

"Oh, it's difficult."

"I plan to start with mountaineering enthusiasts. Has Captain Chu checked this aspect?"

"We've checked it, and there seems to be nothing unusual at the moment, not as much progress as on the deceased."

"Well, the murderer committed the crime over a long period of time, and there are many victims and suspects. Since we have limited manpower, it's better to focus on one aspect rather than two."

"That's what I mean. Okay, I won't disturb Team Tan's work anymore, bye."

"Goodbye, Captain Chu."

Tan Yi put down the phone. He felt that Director Yang and Captain Chu were both okay and open-minded, but the two forensic doctors were a little lacking.

Who is he looking down on!

Would he bring a useless trainee forensic doctor to participate in such an important case?

What a joke!

He patted the information and thought to himself, whether our Xiao Xie can turn things around depends on you.

...

As soon as he got to work the next day, after Tan Yi arranged the tasks, he immediately called Wang Xinyang.

Wang Xinyang was still dreaming. Although he was dissatisfied with Tan Yi for interrupting his beautiful dream, he dared not be inattentive to receive him because it involved a murder case.

At 8:20, Tan Yi and Li Ji knocked on the anti-theft door of Wang Xinyang's house and sat on the sofa chair.

Wang Xinyang asked his wife to pour hot water and smoke cigarettes, and said with his legs crossed: "Captain Tan, I asked around yesterday and heard about the Tiger Tooth Mountain incident. But I don't understand why this incident has anything to do with us. Who has nothing to do with climbing that broken mountain? Not to mention climbing it, I haven't even thought about it."

He was in a leisurely posture, with a wronged expression, and a sense of watching the excitement.

Tan Yi knew that if it weren't for his good psychological quality, this case would be unlikely to be related to him.

But he still wanted to deceive him: "I heard that copper mines are generally accompanied by gold mines..."

Wang Xinyang involuntarily put down his left leg, "Captain Tan, you can't spit blood on me. My father is an honest businessman. He only mines copper mines and has nothing to do with gold mines."

Tan Yi looked around.

Li Ji felt a little puzzled, but he also followed his gaze and finally landed on Wang Xinyang's wife - this person was a golden person, with two gold rings, two gold bracelets, two gold earrings, and a thick gold necklace.

In the Duobao Pavilion, there were three golden arhats, two gold foil paintings of sailing ships, and even the toothpick holder on the tea table looked like it was made of gold.

Wang Xinyang's forehead was covered with shiny beads of sweat, and he said, "My wife likes gold, and those are all copper-plated, not real gold. If Captain Tan likes them, I can give you eight or ten."

His voice was trembling when he said the last sentence.

Tan Yi remained calm, "I was just asking casually. Whether you have violated the law in this regard is up to the relevant departments to investigate. I am just asking some questions as usual, and I hope to get your cooperation."

Wang Xinyang said, "Of course, of course. As long as Captain Tan asks, I will tell you everything I know."

"Is your grandfather still alive?"

"He passed away eight years ago, yes, on August 15th eight years ago.

" "Where is the ancestral tomb?"

"My ancestral home is Guanmenshan, Lishan County. My grandpa is buried there. It has good feng shui."

"Did your grandpa die in your hometown?"

"Yes, the funeral alone took half a month. It was a lot of trouble."

"Besides you and Che Zhe, are there other people joining your gang?"

"What gang? It sounds like a criminal gang. We usually play together in groups of five or six."

"Are you guys on good terms?"

"Not bad. We just eat and drink together and see who wears better clothes, but nothing serious."

"What about Chezhe, is he the same?"

"He, he's better than me, he's been working for his father."

"What did he do in the mine?"

"This... I'm not sure. He manages finances. No, I think he was in charge of purchasing."

"Is his grandfather still alive?"

"It seems he passed away too. He's buried in Xiang'an County. Oh, it seems not far from Huya Mountain... Oh, you can't say I said that!"

...

After leaving Wang Xinyang's house, Li Ji said angrily, "Even if he didn't kill anyone, his father is suspected of illegally opening a gold mine. Captain Tan, should we report him?"

Tan Yi said, "There's no rush for this matter. Let's talk about it after the case at Huya Mountain is over."

Li Ji stiffened his neck, "Why?"

Tan Yi got on the co-pilot, "I guess he has already called his father. To prevent it from happening, they will definitely take measures immediately. The personnel relationships here are complicated, and it's good for us to be slow. But I want to emphasize that being slow does not mean leaving it alone."

Li Ji got into the driver's room, thought for a moment, and said convincedly, "Captain Tan is smart, I understand, where are we going now?"

Tan Yi said, "To the Che family's mine."