The classic cases that Dr. Li Changyu has solved:

1. The murder of "sawmill".

After Kelly, the flight attendant of Pan Am, disappeared, her husband was considered as the biggest suspect, but this man passed the polygraph test three times. However, it was later reported that the victim's husband was seen dragging a large sawmill in the street that night, and he rented a meat grinder that day.

In the cold winter, Li Changyu tried to melt more than two feet of snow to find evidence, and used a frozen dead pig to mix in the branches and put it into a wood chipper for reduction experiment. In the end, he found 56 broken bones, 2,66 hairs, 3 ounces of meat and a tooth of the deceased. The total weight of these evidences was only 31 grams, but the DNA of the victim was accurately measured.

Subsequently, the police found a worn chainsaw. Li Changyu showed the number of the chainsaw by scientific methods, and finally found out that the murderer was the husband of the deceased.

2. Half a fingerprint solves an unsolved case for 3 years.

One noon, an 18-year-old girl went to the indoor parking lot of a shopping mall. Her car was parked on the seventh floor, but someone found her body on the stairs on the ninth floor. A knife stabbed him in the left chest and pierced his heart. The girl's clothes and trousers are all neat, and there are no signs of sexual assault, but her shoes and purse are gone. A handkerchief was found next to the car, and there was no result after inspection.

this case has become an "unsolved case". For more than ten years, the father of the deceased has never given up his efforts to catch the murderer and sold all his possessions, all of which are helpless. Desperate, he found Li Changyu.

Through the photos on the spot, Li Changyu found blood fingerprints on the tissue box behind the car. They found this tissue box, but the person who handled the physical evidence used the wrong medicine and left no clues. Li Changyu, with the mentality of giving it a try, re-used chemicals and lasers. Everything comes to him who waits, and finally he found half a fingerprint. However, when they searched in the fingerprint file, there was no matching information. Apparently, the killer had no criminal record before.

until the death of the deceased's father, the case was still unsolved. Li Changyu's team never gave up the case. Two years later, a woman came into police sight. The result of fingerprint comparison can't convict her, because there are various possibilities for her fingerprints to be left on the tissue box. For example, she wanted to buy this box of tissue, and her fingerprints happened to be left on it.

So, Li Changyu focused his attention on the handkerchief left at the scene. Because after many tests, the handkerchief has been riddled with holes, but they found a little snot on it. Snuff is often a detail overlooked by many chemists. Fortunately, Li Changyu found DNA in the snot and confirmed that it belonged to the woman.

After 3 years of unsolved cases, the murderer was sentenced to life imprisonment, and the deceased and her father can finally close their eyes.

3. Simpson is suspected of killing his wife.

In p>1994, the murder of Simpson, a former American football player, became the most sensational event in the United States at that time, not only because Simpson was a well-known star in sports, movies and advertisements, but also because of the dramatic development of this case. When chasing Simpson on June 17, the three major television networks in the United States stopped broadcasting all programs at the same time, and all the focus was on the whole process of Simpson being chased by the police.

On June 12th, the police found Simpson's white ex-wife Nicole and one of her white boyfriends assassinated in front of her house. The first murder suspect identified by the police was Nicole's ex-husband Simpson. The police found blood with the same blood type as Simpson at the crime scene, and then found blood in the search of Simpson's residence, and found physical evidence such as gloves and sneakers that matched the traces left at the scene of the accident.

Everything seems irrefutable, but Li Changyu saw the flaw. At half past ten in the evening, Simpson is on the phone. At 11 o'clock, his car picked him up at the airport, and the whole case was committed in just 3 minutes. In such a short time, you have to kill two people with a knife, and you have to rush from the first scene to the second scene, jump into the wall and drop your gloves, then go upstairs to take a shower, destroy all the evidence, and finally get on the bus and rush to the airport. This is more magical than the plot of the movie.

From the first day of the investigation, Li Changyu thought that the murderer should be two people, and the bloody shoe prints found at the scene were also confirmed to be two kinds. However, the police identified Simpson from the beginning and announced the result. In an irreversible situation, the police need to collect enough evidence.

By identifying DNA, some evidence was found to be related to Simpson, but Li Changyu also found that there were preservatives in the blood of DNA, and it was impossible for the blood flowing from human body to have preservatives. Besides, Simpson can't wear that blood glove.

Some people say that this is a leather glove, and it has shrunk because there is blood on the outside, but there is very little blood on the glove. Besides, the wall is 3 meters high, even Jordan can't jump over it. If you climb over, the climbing vines growing on the wall will definitely cut the murderer, but there are no such marks.

The police's so-called evidence simply doesn't hold water. At that time, the trial of the case lasted for 13 months, with twists and turns. The jury finally acquitted Simpson, and only the civil court ruled him responsible for the deaths of the two men.

4. Three generations of grandparents and grandchildren were killed.

There is a family of three in Connecticut. The grandmother in her seventies is aloof from the rest of the world. Her son is born deaf and blind, and her little granddaughter is only seven years old. On a stormy Friday night, three generations of grandparents and grandchildren were killed. The old lady was stabbed more than 3 times, the son was stabbed more than 2 times, and the granddaughter was stabbed 17 times. The blood flowed like a river.

This is the most impressive case in Li Changyu, and the scene is terrible. He and his colleagues first analyzed the motive of the murderer. The family had no money, no enemies and no drugs, so what caused them to be devastated?

At first, the police thought it was the old lady's daughter and son-in-law who did it, in order to seize the inheritance. But Li Changyu found a watch at the scene. After returning, Li Changyu found a hair on this watch, which was tested to have black skin tissue. At the same time, Li Changyu and his colleagues found a big handprint at the scene, like the hand of a black basketball player.

After investigation, Li Changyu's team found that the assistant basketball coach in a middle school in this area was black. He used to be the captain of the basketball team in this school, and he took all the scholarships to play in the west, but later he returned to this small town because of drug abuse.

after targeting the suspected target, Li Changyu and his colleagues found another shoe print, found a matching shoe nearby, and found DNA in this shoe, and finally brought the black basketball assistant to justice. It turned out that he wanted to borrow the phone that day, but later he found that the old lady was alone at home, and he had evil thoughts of murdering her life for money.

5. The rape case of Kennedy Jr.

In the United States, sexual cases are not surprising, but they have attracted much attention because of the famous suspects, such as basketball superstar Kobe Bryant, former US President Bill Clinton and Kennedy Jr.

In p>1991, patricia Bowman, a dancer, sued Smith Kennedy for rape, which caused an uproar. Kennedy Jr. has always been a flower name. Whether it is rape or consensual has become the key to the case.

According to patricia's confession, she and JFK Jr. met in a bar that night and fell in love with each other. Then they strolled and kissed on the beach. Suddenly Kennedy Jr. wanted to have sex with her, but the woman refused. Patricia tried to escape, but struggled for five minutes for the latter. Patricia broke free and fled to the backyard. Kennedy Jr. caught up with her and raped her on the lawn for twenty or thirty minutes.

In Li Changyu's eyes, this is a case with no technical content.

First of all, according to the testimony, patricia struggled on the ground for five minutes, and there must be bruises, skin abrasions or torn clothes on her body, but when the doctor examined the injury, she found that she had no scars and her clothes were not torn.

Second, rape is a kind of aggression. It usually ejaculates within one or two minutes, but it can't last for twenty or thirty minutes.

Besides, if you rape on the lawn for so long, you will leave traces of grass and mud on your clothes. But I didn't find these things on her clothes. This proves that after they had sex on the beach, Kennedy Jr. might say that he would never meet again, and patricia bit Kennedy Jr. in a fit of pique.