A man who looks honest and friendly. During the day, he is a good man, a good husband and a good father. At night, he hides in a dark corner, observing the woman in red and choosing the next “prey.” He was hidden in Baiyin City, Gansu Province, China. From 1988 to 2002, he raped and killed 11 women successively and was called the “Silver Killer”.
Because of his existence, the middle and elementary schools in the city cancelled evening self-study. The girls did not dare to go out alone at night, nor did they dare to wear red clothes for many years.
Old case, solved in one fell swoop
The first crime of the “Silver Killer” was in 1988. At that time, there were almost no cameras on the street, and the murderer could easily escape. The policemen broke their legs, took police dogs and rode motorcycles, going from house to house, day and night. Visits, investigations, and investigations were all in vain. The police obtained the murderer’s fingerprints at the crime scene, first extracted the fingerprints of the detainees for comparison, and found that the comparison was not matched. The extraction range was gradually expanded to all men with silver household registration, and then compared them one by one with the naked eye. To no avail.
In 1998, the murderer was brutalized and committed four crimes within a year, and people were even more afraid. Many criminal investigators came to Baiyin City, using various methods to catch the murderer. Criminal psychology experts summarized 7 characteristics that suspects may possess, including sexual perversion, withdrawn personality, being alone, agile, and good psychological quality. Based on these characteristics, the police investigated the suspects in Baiyin City and several nearby cities and counties. One hundred thousand adult men have still not found the murderer.
From 1998 to 2015, the Silver City police did not give up their efforts to find the perpetrator, and they have also used the murderer’s genes extracted from the crime scene to find the criminal many times. But the problem is that, just as the fingerprints of hundreds of thousands of people have been extracted and no suspects have been found, testing the genes of hundreds of thousands of people will not only cost a lot of money and time, but it is also likely that no murderer will be found.
The murderer seemed to never be found, but at this moment, the turning point came.
How to screen a person’s genes from the massive gene bank with the minimum cost has become the key to solving the silver case, and the emergence of “gene genealogy criminal investigation” has become the key to the “resurrection” of this case.
In 2016, Gao Chengyong’s uncle Yuanfang Tang was detained. The police obtained the genetic information of Yuanfang Tang’s uncle through blood sampling and entered it into the criminal’s genetic database. After that, the police routinely compared the relevant information of the case with the silver case. When they compared Yuanfangtang’s gene with that of the “Silver Killer”, they found that his gene was similar to the “Silver Killer” gene. High similarity, the two are likely to belong to the blood relationship within three generations. In this way, the police followed the vines and found Gao Chengyong, who was in full accord with the “silver killer” gene, and the silver case was finally solved.
Spread the gene web
”Gene Genealogy Criminal Investigation” is an interdisciplinary technology developed on the basis of genetic technology testing. The biggest contribution of this technology is that it achieves “fuzzy matching”. In the past, after the police collected DNA from the crime scene, they had to accurately match the individual to find the suspect. If the database does not have the person’s DNA, the criminal can get away with it. But gene genealogy technology allows the police to find the suspect’s distant relatives, and then follow the vine to find him, which greatly narrows the search scope.
In practice, geneticists usually compare the similarities and differences between the two types of genes. The first type is the Y chromosome in the sex chromosome, which is only passed from father to son in humans. The STR genome is an important genetic marker in the Y chromosome. Males in the same family have exactly the same STR genome. As long as the SRT genomes of two men are detected to be the same, their kinship can be determined. Tracing the male Y-STR genome can draw a family tree of males in a family.
Similar to the Y chromosome that only exists in males, there is a type of gene that is only transmitted between females, that is, mitochondrial genes. Mitochondria exist in the cytoplasm, and it also carries some genes. Mitochondrial genes can only be passed on from mother to child, and only mitochondrial genes passed on to daughters can be passed on. Therefore, according to the changes in mitochondrial genes, we can draw a family tree of the female side of the family.
Based on the sequencing of mitochondrial genes, the team of molecular biologist Jerry Luholnos at the University of Liverpool claimed that they had found out the true identity of the British serial killer Jack the Ripper more than 100 years ago. From August to November 1888, “Jack the Ripper” brutally killed at least five prostitutes in the Whitechapel area of East London, England. During the crime, the murderer wrote many times to relevant units to provoke, but he never fell into the French Open.
Although it has been a hundred years since the crime was committed, the number of books and related research on the case has also increased day by day. However, due to the lack of evidence, who the murderer was said to be different, there was no overlap, which made the case even more confusing.
How did Professor Lu He Lannuo decipher the true identity of the murderer more than 100 years later? He found some murderer’s semen from the shawl of one of the victims, Catherine Edworth, and extracted mitochondrial genes from it. Then, the mitochondrial genes of all the female relatives of the suspects screened by the police that year were tested, and it was found that the mitochondrial genes of a female offspring of the sister of one of the suspects, Alan Kosminsky, were exactly the same as those of the murderer. Thus, the true face of “Jack the Ripper” was finally revealed.
Gene web expansion
With the development of gene sequencing technology and gene genealogy criminal investigation, the true culprits of many unsuccessful cases around the world have been arrested: In 2009, a man named Christopher Franklin in the United States was arrested for possessing a lethal weapon His genes became the ultimate evidence for the police to testify against his father, a serial killer who killed 10 people 17 years ago; in the 1970s and 1980s, a Californian American murdered and raped more than 10 people in a decade. The “Golden State Killer” of dozens of women, after hiding for more than 40 years, was arrested in 2018 when the police detected the genetic profile of their distant relatives; in 2019, the genetic profile of a Canadian man caught the police 32 years ago The murderer who killed a couple-the man’s father.
With the support of gene genealogy for criminal investigation, we also need the support of data sources. Therefore, police departments in many provinces and cities in China have established gene banks similar to fingerprint databases. Zhengzhou City, Henan Province is the first city in China to build a gene bank. In 2014, it already had a gene database covering the whole city. In 2018, the Ministry of Public Security of China issued a three-year plan for gene bank construction, requiring all regions to build local gene banks in three years. In addition to China, the United States, Switzerland, Italy, Germany, Poland, Japan, and South Korea are all building national gene banks.
In addition to the official gene bank, as gene sequencing functions are becoming more powerful and cheaper, many private gene sequencing companies have emerged. People can obtain their own genetic map and genetic information from these companies by providing a piece of their own hair or a bit of saliva, including information on family origin and disease inheritance. The GEDMatch website in the United States is just such a website that provides gene sequencing services. It hangs the customer’s gene map on the website. Anyone can query the gene map of strangers on the website, which is equivalent to a folk gene bank. The police found the genetic map of the distant relatives of the “Golden State Killer” on the GEDMatch website.
The establishment of the gene bank and the development of gene genealogy criminal investigation have made everyone’s genes no longer isolated. Through the gene map of the cousin within three generations of the gene owner, he can finally find himself. Now that the gene network has been established, in the future, with the popularization of gene sequencing technology, as scientists learn more about genes, criminals will be more invisible. “Anyone who walks will leave traces”, the traces will be recognized, and the old case will eventually be solved.