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Genealogy Tools Can Help To Solve Unresolved Criminal Cases

Genealogy is in - only recently a report fascinated the public, according to which scientists have created the largest family tree in the world: Through this 13 million people, mainly in Europe and Nord America, are connected over a period of 500 years.

There are a number of offers on the Internet that allow you to search for your ancestors and thus also for your living relatives. Most people probably hope for positive news when they rummage through old documents or even send in their DNA: It's exciting to see who is related to you in this way.

The case of the "Golden State Killer" makes it clear that such websites are much more than playgrounds for hobby family tree researchers. The US investigators tracked down the alleged serial killer Joseph James DeAngelo with the help of such online portals. At least twelve murders and more than 45 rapes in the 70s and 80s are attributed to the man. Several crime series are said to have been committed by him. Distant relatives of the "Golden State Killer" were hobby genealogists.

How the "genealogy" of the Sacramento police here worked, the office of prosecutor Anne Marie Schubert reported: The investigators compared a trace of DNA found at a crime scene with genetic profiles available on the Internet - and thus narrowed down the number of people who could have been the perpetrators.

This crime scene trace was compared with data of distant relatives of the killer, the district's deputy prosecutor, Steve Grippi, told the newspaper "Sacramento Bee". These relatives, who were probably completely unaware that they were related to a murderer and rapist, had used such a website for their private genealogy research. Their genetic profiles were therefore available online.

Because the genetic material of these families had similarities to the DNA sample secured at the crime scene, the investigators evaluated the family trees of these families and determined which relatives lived where in the USA, how old they are - and whether they were possible perpetrators. This is how they finally came across DeAngelo. The former policeman came into the police's focus because his age matched and he lived in an area where many of the crimes had been committed. During a stakeout of the 72-year-old, investigators were able to secure a DNA sample of the suspect from a discarded object and compare it with the old trace.

The match of DNA profiles was confirmed on Monday evening - on Tuesday, the police then struck and arrested the alleged "Golden State Killer". The man was initially indicted in two 1978 murder cases in Sacramento, with further indictments to follow in other parts of California. DeAngelo is scheduled to appear in court for the first time in Sacramento on Friday.

Exactly which websites the investigators used is unclear. In the United States,, GEDmatch and other providers are particularly popular. The companies denied their cooperation with the police in this case, reports the "Guardian". Cooperation with the authorities would only be possible through legal action, it was said on request at The offer of this company is also available in German. Slogan: "Research your family history".

Because it is unclear how the police investigated in detail here, a debate is currently developing in the USA about the data security of such genealogy portals. This and the privacy of the customers are the basis for the business with the curiosity about the question "Who am I - and who is related to me?". After all, who expects to be part of a police investigation when they entrust their most personal data to such a company?

First Case in Europe

While police in the USA are increasingly resorting to genetic genealogy to solve crimes, a double murder in Sweden is the first case outside North America that could be solved in this way. The missing large piece of the puzzle to solve an unsolved murder case from 2004 was provided by a genealogist: Peter Sjölund, who specializes in genetic genealogy, had offered his services to the Swedish police two years ago to help solve "cold cases", i.e. cases that have not been solved even after a long period of time. He had been inspired by the arrest of the notorious "Golden State Killer" in California, who had been tracked down by comparing his DNA with genetic information from family tree databases. Such online databases are also very popular among Americans with Swedish roots, of whom there are about 12 million - a consequence of the massive emigration of impoverished Swedes to the USA from the middle of the 19th century onwards.

The Swedish Forensic Laboratory showed interest and started a pilot project with Sjölund. However, the initial enthusiasm quickly evaporated when it became apparent that the existing genetic profile of the perpetrator contained far too little information. While the police test DNA samples for about 15 gene markers, genealogists analyse their 700,000, which makes it possible to identify very distant relatives such as sixth-degree cousins. After months of work, the Swedish National Board of Forensic Medicine and the Forensic Laboratory succeeded in obtaining better genetic material from the individual samples.

This helped to achieve a breakthrough: When Peter Sjölund uploaded the perpetrator DNA into a commercial American database at the end of April, almost 900 hits resulted. Most were very remote, but 15 to 20 hits seemed relevant. With these names the genealogist then dived deep into the archives of the Church of Sweden. From the 17th century onwards, the church kept records of all births, marriages and deaths in the parishes. In weeks of work across the centuries, in European and American sources, but also on Facebook, Sjölund searched for connections between the hits, common geographical roots and possible relatives. After examining 600 to 700 people in the 19th century and tracing their family trees to the present day, he ended up with a single family from the Linköping region, from which the perpetrator must have come. At the beginning of June, the police brought a pair of brothers in for DNA testing - and indeed: the genetic fingerprint of the one man was completely identical to that of the double murderer from 2004.

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