As I expected, when my conjecture was said in front of Leng Ao, there was no expression on his cold face, and a trace of disdain flashed at the corner of his mouth, "Is this the common sense of liberal arts students?" Don't you know that DNA is an extremely stable substance? As long as there is a little bit left, even if it is a few years apart, we can extract the DNA. Don't you feel like your IQ needs to be topped up? For these professional issues, non-professionals, it is better not to deliberately show off your own cleverness, so as not to expose your ignorance. ”

Is this forensic humor? His expression was undoubtedly mocking me. I said helplessly, "I understand." If it was a murder weapon, it would theoretically be possible to extract a complete DNA fragment and compare it. Even if it has been handled by the murderer, it should be different from ordinary knives, but what if the murderer has ever been treated with high-strength chemicals such as hydrogen peroxide? Is it possible to extract something on it, or to find something unusual, such as a luminol reaction. But can't extract DNA? ”

Leng Ao's originally arrogant expression disappeared in an instant, as if he had been punched in the face, and after a while, the corners of his mouth twitched: "This...... At that time, we found something, but because we did not extract the complete fragment, we could not give a result of measuring human DNA according to the prescribed procedure. Someone on the knife has indeed been treated with hydrogen peroxide, so ......"

I nodded, "Ordinary people would never think of dealing with it in that way, right?" ”

After saying this, I felt that something indescribable was spreading in my heart, and I didn't care about paying attention to Leng Ao, who was pale, I walked quickly outside, and even Qin Ming, who was accompanying me, forgot to say hello. I heard Qin Ming hurriedly say something to Leng Ao, so I hurriedly followed and whispered to me, "But no one has ever dared to question his authority. Although he was young, he was one of the most authoritative forensic doctors in the city. How did you think that the knife might have been handled? ”

"Nothing, just my instincts, because the knife appeared so strangely that we didn't find any clues. So, I think according to Zhang Hao's personality, he will definitely do something. However, with Zhang Hao's mind, it was absolutely impossible to think about what to do with that knife. "After the euphoria, my heart hung in my throat, hoping that everything was not what I thought it was, that he had not been involved in this case. But if it weren't for him, who would have such a meticulous mind?

Qin Ming grabbed my arm and asked repeatedly, "Are you hiding something from us?" Did you find any clues? Or is it ...... The last time we tried a case together, the mysterious person they mentioned...... Does it really exist? And you still know each other? ”

"Perhaps." I looked at Qin Ming lightly, trying not to make him suspect that I was worried about something. The observation is as meticulous as his, and it is impossible to be completely without feelings, so I can only try my best to hide it. In the previous case, Lin Hao had repeatedly emphasized that he was bewitched by a mysterious person, but because he really couldn't find strong evidence, almost everyone thought that he was making excuses for his crimes, but Qin Ming never seemed to give up the investigation. Rather than letting them know the cruel truth now, it is better to remain silent for the time being. Seeing Qin Ming's thoughtful face, I shook my head: "What we are going to investigate now is Zhang Hao's case, your brain won't be too big, and you have thought of something messy, right?" ”

"Nope." Qin Ming smiled, and his two eyebrows also bent: "I just saw that your expression was too serious, and I was scared by you." Since it's nothing, let's continue to investigate the case. If you find any clues, remember to let us know, and don't forget, we are on the same page. ”

"That's natural. Now I think I can continue to talk to Zhang Hao. That knife may be an important part of solving the case. "I looked back at Qin Ming, if I still doubted it before, then everything else would be revealed.

At the same time, the colleague who rushed to Wei Xueman's home to check the vase also quickly called, because Wei Xueman had never been in the habit of loosening the soil for flowers, so it was not difficult to find out the traces left by the knife. In this way, all our conjectures have been confirmed, and it depends on whether Zhang Hao spits out the truth this time. Not only that, but on Zhang Hao's computer, he also found email exchanges other than work, although some of them were deleted, but those emails were obviously very suspicious. Right now, the comrades in the technical department are trying to recover the emails and see if they can find some clues.

Zhang Hao still had a nonchaltical look on his face, and he looked at me proudly, "What's wrong?" Coming back? Are both of you here? So, what clues have been found? Or is there some so-called psychological trap prepared in order for me to jump into that trap? Don't let me down. ”

Qin Ming put the knife on the table and asked Zhang Hao, "Do you know this knife?" Tell us about its origins? ”

Zhang Hao looked at the two of us carefully, and after a while, he said slowly: "Do you still need me to say?" Isn't this a knife? We used to be in your aunt...... That is, it was found in Wei Xueman's flower pot. Is there anything wrong with this? ”

"We have repeatedly inquired and investigated, and we have been convinced that Wei Xueman did not have the knife in the flower pot before leaving home. There were no signs of prying past the doors and windows, and judging by the situation in the room, it was unlikely that someone had taken the key to enter. Judging by the soil in the pot, the soil was almost half dry when the knife was inserted. In other words, that knife was deliberately inserted into the flower pot after we entered Wei Xueman's room together. "I understated.

Zhang Hao's original smugness disappeared, he looked at the two of us, but did not speak. Apparently waiting for us to continue to speak so that we can think about our next steps.

"Shouldn't you say something first?" I looked at him and said word by word. At this moment, his expression had changed subtly, and it was obvious that the perfect evidence that he had previously thought was unbreakable had cracked. I continued: "Not only that, but the knife matched the wound on Lin Lirou's body, and not only that, but there were also human blood stains on it. I think you may know a little bit about chemistry, but it's not comprehensive, because as long as it's a murder weapon, it will always leave a mark. ”