1, "Sawmill" murder.

After Pan Am flight attendant Kelly disappeared, her husband was considered as the biggest suspect, but the man passed the polygraph test three times. However, it was later reported that the victim's husband was seen dragging a large sawmill on 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 put a frozen dead pig on a branch and stuffed it into a wood chipper for reduction experiment. Finally, he found 56 broken bones, 2,660 hairs, 3 ounces of meat and a tooth of the deceased. The total weight of these evidences is only 365,438+0 grams, but the victim's DNA was accurately detected.

Subsequently, the police found a worn-out chainsaw. Li Changyu showed the serial number of the chainsaw scientifically, and finally found out that the murderer was the husband of the deceased.

2. Half a fingerprint has been solved for 30 years.

At noon one day, a girl of 18 years old 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 went into his left chest and pierced his heart. The girl's clothes and trousers are neat, and there are no traces of sexual assault, but her shoes and wallet are gone. A handkerchief was found beside the car, but 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, which is a helpless move. In desperation, he found Li Changyu.

Through the scene photos, 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. Many things happened, and finally he found half a fingerprint. However, when they searched in the fingerprint file, there was no matching information. Obviously, the killer had no criminal record before.

Until the death of the deceased's father, the case remained unsolved. Li Changyu's team never gave up this 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 stay on the tissue box. For example, she wants to buy this box of paper towels, and her fingerprints just left on it.

So, Li Changyu focused 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 that many chemists ignore. Fortunately, Li Changyu found DNA in her nose and confirmed that it belonged to the woman.

After 30 years of unsolved cases, the murderer was sentenced to life imprisonment, and the deceased and her father could finally close their eyes.

Simpson is suspected of killing his wife.

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 famous star in sports, movies and advertising, but also because of the dramatic development of the case. /kloc-during Simpson's pursuit in June/July, 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's pursuit by the police.

On June 12, 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 sports shoes that matched the traces left at the scene of the accident.

Everything seems irrefutable, but Li Changyu saw the flaw. In the evening 10: 30, Simpson is on the phone. 1 1 o'clock, his car came to pick him up at the airport, and the crime time of the whole case was only 30 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 there could not be preservatives in the blood flowing out of human body. Besides, Simpson can't wear that bloody glove.

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

The so-called evidence of the police is untenable. At that time, the trial of the case lasted 13 months, and the jury finally declared Simpson innocent, and only the civil court decided to be responsible for their deaths.

4. The situation of three generations.

There is a family of three in Connecticut. This grandmother in her seventies is isolated from the world. Her son was born deaf and blind, and her little granddaughter was only seven years old. Three generations of grandparents and grandchildren were killed on a stormy Friday night. The old lady was stabbed more than 30 times, her son was stabbed more than 20 times, and her granddaughter was stabbed 17 times. Rivers of blood.

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. There is no money, no enemies and no drugs at home, so what caused them to collapse?

At first, the police thought that the old lady's daughter and son-in-law did it to seize the inheritance. But Li Changyu found a watch at the scene. After coming back, 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. He went to the west with all the scholarships, and later returned to this town because of drug abuse.

After locking the suspect, 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. Later, when he found the old lady alone at home, he had the evil idea of murdering her life for money.

5. Kennedy Jr. rape case.

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

199 1 year, the case of dancer Patricia Bowman suing Smith Kennedy for rape 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 Kennedy Jr. met in a bar that night. 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 the latter for five minutes. 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 she must have bruises, skin abrasions or torn clothes. However, when the doctor checked the injury, he found that she had no scars and her clothes were not damaged.

Secondly, rape is an act of aggression. Usually ejaculate within a minute or two, but not for twenty or thirty minutes.

In addition, rape on the lawn for so long will leave traces of grass and mud on the clothes. But I didn't find these things on her clothes. This proves that they are in after making love on the beach. Kennedy Jr. may say that they will never meet again. Patricia bit Kennedy Jr. in a rage.