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Genetic mysteries: Should your data be used to solve crimes?

At Front Line Genomics, we tend to focus on the health implications of scientific advancements. But one especially important use of genomic data is not found in the clinic; rather, it is used by investigators to solve crimes. But what are the wider implications of this?

In this feature, we explore the role of genomics in criminal investigations, and the moral questions that have popped up as technology advances.

How can genomics be used to investigate crimes?

DNA has been known to be the genetic material of cells since the 1800s, but the use of this biological matter to solve crimes is a relatively recent development. The first instance of this was in 1986, when DNA fingerprinting (matching alleles at various loci between a sample and a suspect) was used to exonerate an individual who had been accused of rape and murder. Since this first use of the technique, DNA analysis has been a cornerstone of the criminal investigation process.

As technology advanced, the potential to use genomic data to pin down a suspect grew. However, even the highest quality DNA sample from a crime scene is only useful if you have something to compare it to, meaning that the data could only supplement existing evidence that had already brought a suspect to light. In cases where there were no leads, DNA evidence was largely unusable.

The early 2000s saw the introduction of familial testing in the UK, which compared DNA left at crime scenes to that of individuals in the National DNA Database to identify any family members. This technique was, however, relatively unreliable. So, how has this field developed?

What is DNA Fingerprinting?

DNA fingerprinting, also known as DNA profiling or genetic fingerprinting, is a powerful forensic technique used to identify and analyse an individual’s unique genetic characteristics. The process involves extracting DNA samples from biological materials and employing various molecular biology techniques, such as polymerase chain reaction (PCR) and gel electrophoresis, to create a distinct pattern of DNA fragments. This pattern, referred to as a fingerprint, is unique to each individual, except in the case of identical twins. By comparing the DNA fingerprints of different samples, forensic scientists can determine relationships, identify individuals and establish or exclude potential matches in criminal investigations, paternity cases and other areas of genetic research. DNA fingerprinting has proven to be a revolutionary tool in the field of forensic science, offering relative accuracy and reliability when determining the identity of individuals.

The Golden State Killer

DNA fingerprinting and familial testing, once revolutionary techniques in the investigator’s toolbox, haven’t always been enough to solve crimes, especially when dealing with cold cases. With the advent of new genomic technologies and the rise of direct-to-consumer testing, law enforcement officials began to search for new ways to use DNA to track down criminals.

Perhaps the most famous example of DNA solving a long-standing cold case is that of Joseph James DeAngelo, AKA The Golden State Killer. The moniker referred to an unidentified serial killer, rapist and burglar who committed a series of crimes in California in the 1970s and 1980s. The perpetrator was responsible for at least 13 murders, 50 sexual assaults and over 100 burglaries. The case remained unsolved for decades, making it one of the most notorious unsolved crime sprees in US history.

A breakthrough in the case came decades later in 2018, when law enforcement officials used a novel approach called ‘investigative genetic genealogy’ to track down the perpetrator. Investigators took DNA evidence from one of the old crime scenes and uploaded it to GEDmatch, a public genealogy database that allows users to upload their genetic data to find relatives and build family trees. By comparing the DNA sample to those in the database, investigators identified relatives of the Golden State Killer, and using traditional genealogical research constructed family trees to trace potential suspects. Eventually, they narrowed down the list of suspects and identified Joseph James DeAngelo as a potential match.

Law enforcement then obtained a discarded item with DeAngelo’s DNA, confirming a match to the Golden State Killer’s profile. In April 2018, DeAngelo, a former police officer, was arrested and charged with multiple counts of murder and other crimes related to the Golden State Killer case.

In June 2020, DeAngelo pleaded guilty to 13 counts of first-degree murder and numerous other charges, admitting to all of the crimes attributed to the Golden State Killer. Two months later, he was sentenced to life in prison without the possibility of parole. In the years since his conviction, US law enforcement have used the method to solve over 200 cases.

What is investigative genetic genealogy?

Investigative genetic genealogy (IGG) is a cutting-edge forensic technique that utilises DNA profiling and genealogical databases to identify individuals or solve crimes by tracing their familial relationships. This method involves comparing crime scene DNA profiles with publicly available genetic databases, such as those provided by direct-to-consumer testing companies. By identifying genetic relatives and building family trees through genealogical research, investigators can narrow down potential suspects. The data can be obtained from many companies (should a warrant be obtained) and larger databases such as GEDmatch, which allows for third-party assessment of data from other companies. As of 2019, over 26 million people worldwide had genetic data stored in one or more of these databases.

A global issue

The USA isn’t the only nation employing investigative genetic genealogy techniques to solve crime. In 2020, after the conviction of the Golden State Killer and lengthy legal considerations, Swedish law enforcement chose to carry out a pilot study of the method in an attempt to solve a 16-year-old cold case. The double-murder of a young child and a 56-year-old woman in 2004 had shocked the nation, and despite leaving DNA at the crime scene, the perpetrator had never been found.

By analysing the leftover DNA and uploading it to GEDmatch and other databases, distant relatives of the killer were identified. The genealogy step resulted in the identification of two brothers, one of whom ultimately matched the DNA found at the scene. He confessed to and was convicted of the murders nearly two decades after they had taken place.

But the success of the method in this case was not quite enough to prove that it should become standard. Whilst it was determined that the use of investigative genetic genealogy was necessary to drive forward progress in this particular cold case, there are still a number of barriers remaining to justify the use of this method in a wider context. Additionally, although the chances of finding at least one distant relative using this method are high, technical challenges remain due to the often-low-quality nature of the DNA left at crime scenes.

The legalities

These cases showcased the potential of using genealogy databases and forensic DNA analysis to solve cold cases. However, this has led to discussions about privacy and ethics. Should your DNA be made available to law enforcement if you did not consent to this when you first provided samples?

This question has been extensively considered and many countries have released guidance on the matter. In several nations, genetic data is considered to be sensitive personal information and is subject to privacy and data protection laws. By obtaining this data from genealogy databases – where users uploaded it for one distinct purpose – law enforcement may be entering a grey area. Not only do we have to consider the privacy of any suspects, but we also must consider the relatives whose data is being accessed.

In the case of the Swedish pilot study, it was ultimately decided that the benefit of removing a violent criminal from the streets outweighed the concerns around privacy. After the case was concluded, a report stated that the method was effective enough to warrant use in the ‘right circumstances’ with ‘extreme care’. But where can we draw the line between public safety, and personal safety when it comes to our data?

In the UK and most European countries, the processes involved in this method are still unregulated, whilst in Germany the analysis used in investigative genetic genealogy is explicitly illegal. Additionally, most genetic databases still require a warrant for access and where this isn’t the case, individuals can typically opt-out of data being shared with law enforcement. In the EU, all individuals are automatically opted-out in line with GDPR. It is therefore no surprise that investigative genetic genealogy has been used far more extensively in the US.

A moral issue

But if the technique is so effective at catching violent criminals, why wouldn’t we want to use it? What is so precious about our DNA?

Ultimately, the use of genomics has been instrumental in advancing healthcare globally. Without individuals willingly handing over their data, many advancements simply could not have happened. Participating in these studies requires trust in researchers and the ethical handling of data, which is particularly relevant when it comes to many underserved communities. By retroactively repurposing this data, we risk breaking this trust, and hindering scientific advancement. Moreover, many fear that if the terms of direct-to-consumer testing change to allow data sharing in the case of criminal investigations, then a precedent has been set. Some believe this could lead to the sharing of genetic data with insurance companies, for example. This latter issue is a significant argument in the opposition to mandatory DNA databases, where sequences would be recorded at birth from all individuals.

Another argument is the potential for errors when it comes to this technology. Whilst the data tends to be accurate, there is always the potential for something to go wrong. Investigative genetic genealogy in particular is a relatively new field, and there are still many questions to be answered to ensure that innocent people are protected. Furthermore, a fear of abuse from law enforcement and potential discrimination based on genetic evidence is another problem that must be addressed.

These issues serve as a stark reminder that all individuals, even those who may have committed crimes, must be able to trust science for the good of all people. Different nations are currently addressing the moral and legal challenges associated with investigative genetic genealogy, and the UK regularly updates its guidance on forensic information databases. Ultimately, we must ensure that all individuals give fully informed consent before handing over their data, prior to a new revolution in the field.