In the face of Lao Ji's inquiry, Zhang Ji still denied it, saying that potassium Q is a strictly controlled experimental product, and every expenditure is recorded in detail and cannot be lost.

Lao Ji said that it was during his duty time that there was a significant deviation in the record. Zhang Ji couldn't hide it anymore, so he admitted that he was afraid of taking responsibility and secretly changed the record.

Sister Xi confirmed Zhang Ji's statement from the hotel waiter, and he did not leave until midnight, which means that Zhang Ji could not have killed Zhu Fengfan with his own hands.

Later, Sister Xi reported that potassium Q was found in Zhang Ji's house, and she also found out that Zhu Fengfan had been in contact with Zhang Ji very frequently recently.

She learned from Zhang Ji's colleagues that Zhu Fengfan used to be a chemistry teacher at that university, and later started a joint venture with someone to start a chemical product with a project, and his relationship with Zhang Ji was also very complicated.

Zhang Ji's economic situation is not good, he has not yet started a family at the age of 30, Zhu Fengfan introduced a girlfriend to Zhang Ji, this woman turned out to be Zhu Fengfan's subordinate, divorced, and later Zhu Fengfan's wife died, but he backhanded and pried away Zhang Ji's girlfriend as his wife.

That's right, this woman is Liu Mei, it is because this Zhang Ji is often ridiculed by his colleagues, so Zhang Ji hates Zhu Fengfan very much, and definitely has the motive to kill Zhu Fengfan, but they have been in close contact recently.

This made Lao Ji very puzzled, Sister Xi analyzed, it stands to reason that Zhu Fengfan should try to stay away from Zhang Ji as much as possible, but Zhu Fengfan has recently gone to Zhang Ji's laboratory three times and twice. warned Zhang Ji in front of his colleagues, told him to stay away from Liu Mei, and riveted Zhang Ji with all his might.

Zhang Ji once threatened to make Zhu Fengfan die well. At this moment, Cuong reported that Zhu Fengfan's lockbox had been found.

The lockbox was found in the grass on the side of the road, and it seemed that everything else was still there except cash. Xiao He found that the box had been pried open, and found a piece of paper in the crack of the box.

It reads: If he has an accident, it must have something to do with Zhang Ji.

Sister Xi also found biological enzymes on the box.

Lao Ji speculated that someone should have sneezed into the box, and if it was left by the murderer, then the murderer's DNA could be extracted.

Sister Xi collected a DNA sample from Zhang Ji, and Lao Ji asked Zhang Ji again what happened to the potassium Q found in his house.

Zhang Ji said that there are many rats in the house, and these potassium Q liters are used to kill mice. Lao Ji said that as long as he made a phone call, he would be clear to his mother. Zhang Ji was silent, and Zhang Ji said that Zhu Fengfan had been approaching him frequently recently. Zhu Fengfan's actions were a provocation to him, and he didn't bother to take care of him.

And he also admitted that he had threatened to Zhu Fengfan not to die well, he was planning to kill Zhu Fengfan, but he didn't expect that before he could do it, Zhu Fengfan died.

After learning that Zhu Fengfan died of potassium poisoning, Zhang Ji excitedly denied that he killed Zhu Fengfan.

At this time, Cuong reported that Zhu Fengfan's children were eating when they were both taken to the hospital with food poisoning, and the doctor suspected that someone had poisoned him, and it was potassium Q.

This shocked Lao Ji, and Ah Qiang also said that Liu Mei, who was eating together, was not poisoned and is now taking care of the child in the hospital.

Liu Mei said that the meals were all made by him, and she simply fried a few dishes, and she was not poisoned because she was a vegetarian, and she suspected that the sauced beef might have spoiled.

When Cuong told her that the two children were suffering from potassium poisoning, Liu Mei was also surprised and brought the police to the house. Xiao He planned to pack all the meals back for inspection, Liu Mei said that there was still a small piece of sauce beef left in the refrigerator, and when she was about to get it, Xiao He stopped her, and Xiao He asked her if anyone else had touched the refrigerator in the past two days except her.

Liu Mei replied no, Xiao He took fingerprints on the handle, and asked if she and her husband had the habit of wearing gloves when opening the refrigerator, Liu Mei said that there was no such cleanliness, could it be that Xiao He found something.

Xiao He found out that the saliva in the lockbox was left in the last few days, not Zhu Fengfan, and it had nothing to do with Zhang Ji.

Through handwriting identification, the note was indeed written by Zhu Fengfan.

Lao Ji was puzzled, the content of the note pointed to Zhang Ji, but there was indeed someone else who opened the lockbox. Ah Qiang searched Liu Mei's house and found semi-Q potassium.

He reported that Liu Mei's meals at home had been tested for poison, and only the sauced beef contained potassium Q, and the sauced beef in the refrigerator also contained potassium Q, which was presumably injected with a syringe.

Lao Ji analyzed that Liu Mei should not be the real poisoner, because if she wants to poison Zhu Fengfan's children, she can directly poison the food, and there is no need to inject it into the whole meat first and then cut it up.

Xiao He inspected the Q potassium bottle that Ah Qiang brought back, and the fingerprint on the top of the bottle was Zhu Fengfan's, so why did he poison his refrigerator, both of them were puzzled.

No other people's fingerprints were found on the refrigerator except for Liu Mei's fingerprints, but Xiao He concluded that the poisoner was someone else, because he checked and found that the traces on it were left by someone who opened the refrigerator with gloves recently.

And the plate with the sauce beef also has the same lines, so could it be that someone sneaked into her house and poisoned her?

Xiao He said that the doors and windows of Liu Mei's house were intact and there were no traces of sneaking in, and Lao Ji thought that Liu Mei had lied.

Sister Xi and Ah Qiang came back from the hospital and said: Zhu Fengfan's son reported to him some things that Liu Mei did not explain. Zhu Fengfan's remarriage was strongly opposed by the children, who suspected that Liu Mei was coming for their family property, and finally under Liu Mei's repeated insistence, Zhu Fengfan made a will, except for the house where Liu Mei now lives, all other properties of Zhu Fengfan are inherited by the children.

Zhu Fengfan's son also said: When they were sorting out their father's belongings, they found that Zhu Fengfan had secretly insured 1 million personal accident insurance. Liu Mei was the only beneficiary, and it was also discovered that Zhu Fengfan's chemical plant had been ordered to close for violating environmental protection laws.

His partner absconded with donations, and Zhu Fengfan not only faced prosecution and fines, but also a large amount of debt. Zhu Fengfan went on a business trip this time just to go out for activities, but it was obvious that he returned in vain.