After receiving the call from Yu Shan, psychology professor Hu Yada quickly rushed to the Second Criminal Investigation Team.
Li Qi was a little surprised when he saw Professor Hu Yada: "Professor Hu, long time no see! I didn't expect you to be in Nanshi now!"
"Master, do you know Professor Hu?" Han Cheng looked confused.
"Of course we know each other. When we were in Jade City, we worked together on many cases! But it seems like we have been apart for more than ten years!"
Li Qi spent some time in the Jade City Criminal Police Team more than ten years ago. At that time, Professor Hu Yada was already a well-known psychology expert.
"Brother Li, I didn't expect to meet you here! You haven't retired yet?"
Seeing Li Qi again, Professor Hu Yada seemed a little surprised and happy.
"Retire soon!"
The two old brothers, after chatting for a while, got down to business.
"My apprentice Xiao Han said that Mao Ding had strange eating behavior before killing people. Professor Hu, can you help me find out what this behavior of Mao Ding can mean?" Li Qi said.
Then, Hu Yada carefully watched the video of Mao Ding before and after the murder, and then frowned: "Just relying on the details of what he ate cannot explain anything. You need to know what he ate to make further judgments! "
"Professor Hu, is there anything that can cause mental illness to relapse after being eaten by mentally ill patients?" Han Cheng asked.
"Yes! For example, some schizophrenia patients who are sensitive to chili peppers may suffer a relapse of psychosis after eating chili peppers!"
"Also, overdose of medication by mentally ill patients may lead to relapse of mental illness!"
"If you want to know what the murderer ate before getting sick, you need to test his oral saliva and blood in time. Otherwise, over time, the test data will be inaccurate!"
After listening to Professor Hu Yada's words, Li Qi immediately ordered Lan Ru to test Mao Ding's saliva and blood.
It was found that Mao Ding's saliva and blood contained drugs used to treat mental illness.
Moreover, the drug content in the blood greatly exceeded the standard drug content.
This shows that what Mao Ding was taking before his onset of illness should have been drugs to treat mental illness.
But this does not prove that Mao Ding committed murder intentionally.
He could bite the bullet and say that he was taking medicine to treat his mental illness.
As for the overdose, he could argue that he was in a daze at the time and could not remember how much he had taken.
When the police later interrogated Mao Ding, he did indeed defend himself in this way.
However, after Han Cheng and Professor Hu Yada looked at Mao Ding's every move before taking the medicine again, they found that he was no different from a normal person. He walked normally and could greet acquaintances normally.
This shows that his mental state before taking the medicine was normal. There was no situation like Mao Ding said that he was already mentally disturbed when taking the medicine and did not know how much medicine he had taken.
But this alone is not enough!
If Han Cheng can find Mao Ding's motive for murder, there may be a chance for the case to be overturned.
Indeed, if Mao Ding is to be prosecuted for intentional homicide, the motive for the murder must be clarified.
Judging from the video, Mao Ding's murder seemed to be impromptu. Without saying a word during the whole process, he stepped forward and stabbed to death the convenience store clerk who was sorting the shelves.
Then he went out to the door and saw the grandfather and grandson walking on the road. He stabbed them with a knife until they fell to the ground and could not move.
After that, the murderous Mao Ding continued to attack passers-by, but because everyone was on guard, Mao Ding did not hurt anyone else until the police arrived at the scene and captured him alive.
Han Cheng fell into deep thought while watching Mao Ding's murder video.
If Mao Ding wants to use mental illness to kill people, who is he going to kill?
Is it the female convenience store employee, or the grandfather and grandson?
Judging from the video, the grandfather and grandson were passers-by who happened to be passing by, and they should not be the targets of Mao Ding's attack.
Perhaps the female convenience store employee was Mao Ding's target.
Han Cheng once again watched the surveillance video of Mao Ding after taking medicine frame by frame.
After taking the medicine from Maoding, although he was a little wobbly when walking, the direction he wanted to go was clear. He kept walking towards the convenience store.
After arriving near the entrance of the convenience store, he stood there and watched for a few minutes. Then he suddenly rushed into the convenience store like crazy, picked up the fruit knife sold on the shelf, and stabbed the female clerk.
From the time Mao Ding stayed at the convenience store until he entered the convenience store and then skillfully picked up the fruit knife on the convenience store shelf, Han Cheng concluded that this was not the first time Mao Ding visited this convenience store.
He suspected that Mao Ding had had any conflicts with the female clerk before.
So Han Cheng asked the convenience store owner to retrieve the surveillance video from the store within half a month.
After watching the surveillance video, Han Cheng discovered that this was not the first time that Mao Ding committed the crime. He had visited the convenience store a few days before the incident.
There was also a dispute with the female convenience store employee, the deceased woman.
The reason for their dispute was that the female employee suspected that Mao Ding had taken a fruit knife and did not pay her, but Mao Ding insisted that he did not take a fruit knife.
Just when the two were red-faced and refusing to give in to the other, a customer picked up a fruit knife from the ground and handed it to the female clerk, and the conflict was resolved.
Through the surveillance video, Han Cheng saw that it was Mao Ding who accidentally knocked a fruit knife to the ground while picking up other things, and then accidentally kicked it into the bottom of the shelf. He was not aware of it at the time.
When the female clerk saw that Mao Ding was missing a knife after passing the shelf selling fruit knives, but Mao Ding did not take out the fruit knife to scan the code to pay, she thought that Mao Ding had hidden the fruit knife on his body.
Could Mao Ding have the motive of revenge and murder because of this little conflict with the female clerk?
Han Cheng and others asked Mao Ding's friends, and their evaluations of Mao Ding were surprisingly unanimous: This person has a small mind, and he will retaliate!
In the face of various evidences, Mao Ding finally confessed.
His motive for the murder was to avenge the female employee who had wronged him.
He killed someone in revenge for a minor conflict, and also involved two innocent lives.
It is not an exaggeration to describe Mao Ding's crime as heinous.
The Second Criminal Investigation Team finally prosecuted Mao Ding for intentional homicide.
With all the evidence found by Han Cheng and the authoritative conclusion of Professor Hu Yada.
It is certain that Mao Ding will be sentenced to death this time.
