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FALQs: The Use of DNA from Genealogy Sites to Solve Crimes in Sweden

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This blog post is part of our Frequently Asked Legal Questions series.

A Swedish-American reading his Swedish newspaper. Photo by Jack Delano (Apr. 1942). Library of Congress Prints and Photographs Division, //

This past weekend (September 27) marked national Ancestry Appreciation Day. It made me think of a recent criminal case in my ancestral Sweden that was solved with the help of genealogists. Later this week, on October 1, 2020, the District Court in Linköping is scheduled to render a decision on the charge of murder in this 16-year old cold case where the suspect was ultimately identified with the help of DNA found on a genealogy site.


On June 9, 2020, a 37-year-old man was apprehended as the prime suspect in the killing of two persons in Linköping, Sweden, on October 19, 2004. The following day, the man was detained pending trial after having confessed to the acts of killing an 8-year-old boy and a 57-year old woman, seemingly unprovoked. The arrest was a major breakthrough as the 16-year -old case had been cold for years, even though the murderer had left both DNA and fingerprints at the crime scene. But neither matched information stored in the police’s own DNA registry of suspects, or the fingerprint registries of already convicted persons. Because the woman was still alive when police arrived at the scene, she was able to provide a description of the killer to the officers, which was later confirmed by the DNA.

Thus, early in the investigation the police knew that the killer was male, in his early twenties, and had blue eyes. But it was not until investigators used DNA found on commercial genealogy sites that they got any closer to finding the killer. How the case was solved bears resemblance to that of the Golden State Killer case, in California, which was also solved by finding relatives of the suspect’s DNA that the police had on file, using genealogy sites. In this Swedish case the police specifically used DNA from the genealogy sites Gedmatch and Familtytree to match with DNA from the crime scene – locating relatives of the suspect, and narrowing in on the suspected murderer as a potential match using the known factors of age and sex.

Intrigued by how the case was solved, I wanted to share with you what DNA registries exist in Sweden and how they may be used by law enforcement.

  1. What rules govern criminal investigations?

Criminal investigations are governed by chapter 23 of the Procedural Code (Rättegångsbalken (SF S1972:470) (RB)). In accordance with 23:1 RB an investigation must be conducted as speedily as possible.

Further regulations are also found in Förundersökningskungörelse (SFS 1947:948), which includes rules for when persons may be called for questioning. (6 §.)

Suspects may be held pending trial (23 kap. RB). You can read more about pre-trial detention here.

  1. When can DNA be collected from a suspect?

Chapter 28 of the Procedural Code specifies when the DNA of a suspect may be collected. In order for police to collect DNA, a person must be suspected of a crime that is punishable with a prison sentence. (28:12a RB.) The police may collect saliva samples from anyone who is justifiably suspected (skäligen kan misstänkas) of a crime, the lower level of suspicion. (28:12a RB.) In addition, DNA samples may be collected from others if:

  1. the purpose is to, by DNA analysis, facilitate identification during the investigation of a crime which is punishable with imprisonment, and
  2. there are exceptional reasons to believe that it is of value to the investigation of the crime.

The DNA analysis result may not be compared with the DNA profiles that are recorded in registries of DNA profiles that are kept in accordance with the law (2018:1693) on police use of personal information within the crime data law or otherwise is used for a purpose other than that for which the sample was taken.” (28:12b RB.)

Any DNA collected must be treated in accordance with the rules in the Act on Police Use of Personal Information within the area of the Crime Data Act (Lag (2018:1693) om polisens behandling av personuppgifter inom brottsdatalagens område). These rules include, among others, provisions on how long DNA may be kept in the registry. (5 kap. 7 §.) For example, DNA of convicted criminals may only be retained as long as they are part of the official police records (belastningsregistret), the duration of which is dependent on the severity of the crime. 

  1. Are there DNA registries in Sweden?

 There are several DNA registries in Sweden. The Swedish National Forensic Centre (Nationellt forensiskt centrum (NFC)) controls three different DNA registries: the DNA registry (DNA-registret), the DNA registry for investigations (utredningsregistret), and the DNA registry for evidence from crime scenes (spårregistret). (5 kap. 1 § Lagen (2018:1693) om polisens behandling av personuppgifter inom brottsdatalagens område.) The Police DNA registry includes DNA samples of all persons who have been sentenced, by a legally binding verdict, to a sanction other than payment of a fine, or who have accepted a summary imposition of a suspended sentence. (Id. 5 kap. 2-3 §§). The DNA registry for Investigations includes DNA profiles collected in accordance with chapter 28 of the Procedural Code, from persons justifiably suspected of crimes for which imprisonment may be imposed. (5 kap. 4 §.) The DNA Registry over evidence from crime scenes may include DNA profiles found at crime scenes that cannot yet be linked to an identifiable person, and content from this database may be cross referenced with other DNA databases, and when identified will be transferred to that database. (5 kap. 5-6 §§.)

In addition, the police keep a Police Elimination DNA database, which is a database of DNA from persons who regularly come into contact with crime scenes, such as police detectives etc. The purpose of the database is to eliminate DNA when evaluating DNA from a crime scene. (Lagen (2014:400) om Polismyndighetens elimineringsdatabas.)

In addition to the police databases mentioned above, Karolinska Institutet maintains a registry that includes DNA information (commonly known as the “PKU registry” for collecting information that tracks the effects of phenylketonuria (PKU), the inability to metabolize phenylalanine.) Starting in 1975, all babies born in Sweden had their blood tested and deposited in a bio-bank. The purpose of the bank is to collect information for scientific research within the field of medicine, including tracking the disease phenylketonuria in particular. (5 kap. Lag (2002:297) om biobanker i hälso- och sjukvården m.m.) It can, however, also be used by police to confirm or disprove a person as a suspect, but only if the police obtain a court order, which requires that the police show the person is suspected of the crime on reasonable grounds . (28:1 RB.) Because the police did not have a primary suspect for the 2004 double murder, this DNA registry could not be accessed. However, as he was born in Linkoping in 1983, the suspect in the 2004 double murder is part of this registry.

The PKU registry was used in the investigation of the murder of Sweden’s Foreign Minister Anna Lindh in 2003, when the blood sample of suspected murderer Mijailo Mijailovic was tested and determined to match the DNA found at the crime scene. It has not been used since, and in cases where the police has a named suspect it has the power to take a DNA sample against the will of the person. (28:12a RB.) Thus, use of the PKU registry would be most useful in cases where the known suspect cannot be located or is deceased.

The use of the PKU registry to solve an aggravated assault case was denied in 2018, when the Supreme Court reinforced the rule that access to the registry requires exceptional circumstances. (Supreme Court case NJA 2018 s. 852.) 

  1. When can DNA from family members be used?

On January 1, 2019, a new law on police treatment of personal information within the area of the Crime Data Act (Lag (2018:1693) om polisens behandling av personuppgifter inom brottsdatalagens område) entered into force, thereby revoking the Police Data Act (Polisdatalagen (2010:361)). In accordance with the new, law police may conduct “family searches” of DNA that is contained within the police DNA registries “for the purpose of obtaining a sample of persons based on genetic or health data in the forensic activity.” (6 kap. 5 §; Prop.2017/18:269 at 173.)

  1. How was the DNA obtained in the recent murder case?

DNA from the murder scene was collected both from the knife and the victims, as well as a beanie hat the perpetrator left behind when fleeing the scene. Once analyzed, the forensic experts could determine that the person who committed the crime was blue-eyed, and in his twenties when the crime took place. The police proceeded to test the DNA of 5,000 men who fit that description in search of the perpetrator but were unsuccessful. In fact, the suspected murderer had reportedly been called to come and voluntarily submit his DNA because he fit the profile based on his age, and the fact that he was living in Linköping when the crime took place, but he had chosen not to show up.

When these measures failed, the police solicited help of a genealogist to search for relatives of the perpetrator, and found several men whose relatives had similar DNA to the suspected murderer. Reportedly, the Linköping Police were inspired by the use of genealogy sites to track the Golden State Killer. As reported in Swedish media, the two genealogy sites that were used were Gedmatch and Familytree. 

  1. Has DNA or information from genealogy sites been used before in Sweden?

This is the first time DNA recorded with a commercial genealogy site has been used. But it is not the first time genealogy and family DNA has been used to solve a cold case. In 2019, the police managed to solve a 24-year-old child rape case by searching for family members in the police DNA registries. The rapist was found and convicted. That case was slightly different, as in that case the use of the DNA from the crime scene generated a “relative match” in the police’s own DNA registry. Thus, by running the DNA from the crime scene against the DNA registry of previously convicted persons, the police found a person who was related to the rapist. The police then proceeded to use commercial genealogy sites to uncover that individual’s relatives, finding a few potential relatives, one of whom was tested and confirmed to match 100% with the rapist. The man was later convicted in court and is currently serving a six-year prison term.

  1. Is there any international collaboration?

Earlier this year, a Swedish man was identified as being connected to another cold case using DNA accessed through a German DNA database, using the European rules (Prüm Decision) on sharing of information contained in local DNA databases with the purpose of solving serious crimes. The man is yet to be charged, but the prosecutor has stated that the prospects of a conviction are good.

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