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Golden State Killer’s Arrest: The DNA Breakthrough That Cracked the Case Wide Open!

Unraveling the Killer’s Capture

By Matthew JackPublished 3 months ago 8 min read
The Daily Beast

Joseph DeAngelo, also known as the Golden State Killer, was responsible for a notorious crime spree in California during the 1970s and 80s. His case remained unsolved for over four decades until a breakthrough investigation finally led to his capture. In this article, we will delve into the details of the Golden State Killer case and the groundbreaking investigation behind it.

Reminder, The Crimes of The Golden State Killer

The Power of Genetic Genealogy

Genetic genealogy played a crucial role in catching the Golden State Killer. Investigators collected biological material from crime scenes, such as blood or semen, that contained DNA. This DNA was then sequenced, creating a genetic profile of the perpetrator.

Genetic profile was compared to a public database of DNA sequences, such as GEDmatch, to find potential relatives. By building a family tree based on these relatives, investigators were able to narrow down the suspects and identify Joseph DeAngelo as the Golden State Killer.

Profiling the Perpetrator

To profile the Golden State Killer, investigators utilized a genotyping chip with around 700,000 probes designed to match unique DNA variants. This advanced technology enabled them to isolate the relevant probes in a sample of the perpetrator’s DNA, creating a comprehensive genetic profile.

By comparing this genetic profile to the profiles in extensive DNA sequence databases, investigators could identify potential relatives and construct a detailed family tree. This critical step relied on shared DNA variants, providing valuable clues to help solve the case.

Finding the Relatives

After obtaining the genetic profile of the Golden State Killer, law enforcement took advantage of a public DNA sequence database, such as GEDmatch, that individuals had previously used to upload their genetic sequences for genealogical purposes. By searching the database, investigators looked for genetic profiles that shared many genetic variants with the perpetrator, indicating a close familial relationship. This approach allowed them to identify potential relatives of the Golden State Killer who could provide vital information in the pursuit of justice.

The Power of Shared Genetic Variants

Shared genetic variants are crucial in finding relatives in a DNA database. These shared variants are specific sections or markers within the genetic sequences more likely to be passed on to family members. By analyzing the number of shared variants between the genetic profile of the Golden State Killer and the profiles in the database, investigators could prioritize potential relatives for further investigation.

Identifying these relatives was critical in building the perpetrator’s family tree. The closer the genetic relationship, the more recent the common ancestor, allowing investigators to narrow the search for the Golden State Killer within a specific family branch.

An Ethical Debate

Using public DNA databases for law enforcement has sparked an ongoing ethical debate. While it has undeniably helped solve cold cases like the Golden State Killer, concerns have been raised about privacy and consent. Critics argue that individuals who have uploaded their DNA sequences for genealogical purposes did not anticipate their data being used for criminal investigations. As genetic genealogy becomes more prevalent in law enforcement, balancing pursuing justice with protecting individual privacy rights is crucial.

Building the Family Tree

Building the family tree of potential relatives of the Golden State Killer involved a combination of traditional genealogy techniques and modern methods. Investigators utilized various resources, including birth and marriage certificates, census data, obituaries, and social media stalking to gather information about potential relatives.

Starting with living relatives, investigators meticulously traced their family connections back through distant ancestors. They constructed a comprehensive family tree by piecing together the puzzle of ancestry. This reverse genealogy process was crucial in narrowing the list of suspects.

Investigators relied on various records, such as ancestry records, local archives, and public databases, to uncover the ancestral links. These sources provided valuable insights into the family histories of potential relatives, allowing investigators to refine their search further.

By combining both traditional and modern methods, investigators were able to create a detailed and accurate representation of the Golden State Killer’s family tree. This comprehensive understanding of familial connections helped guide the investigation toward identifying Joseph DeAngelo as the perpetrator.

Identifying the Suspect

Once potential suspects were identified through genetic genealogy, investigators utilized conventional investigative methods to narrow down the choices. This involved comparing the physical features of the suspects to past eyewitness statements and police sketches.

In the case of the Golden State Killer, the description provided by surviving victims matched Joseph James DeAngelo, who was ultimately identified as the perpetrator.

The Capture and Guilty Plea

Joseph James DeAngelo, also known as the Golden State Killer, was apprehended in April 2018 as a result of the combined efforts of genetic genealogy and traditional investigative methods. DeAngelo confessed to the crimes he had committed during his reign of terror and pleaded guilty to multiple counts of murder and kidnapping in June 2020. He was subsequently sentenced to life imprisonment without the possibility of parole.

The arrest of Joseph DeAngelo marked a significant milestone in the decades-long pursuit of justice for the victims and their families. It brought closure to the survivors who had lived in fear for years and finally held the perpetrator accountable for his heinous acts.

The Golden State Killer’s successful capture highlights genetic genealogy’s power in solving cold cases. It demonstrates the effectiveness of collaboration between law enforcement agencies and genetic genealogists. This innovative approach, coupled with the unwavering determination of investigators, ultimately led to the identification and conviction of Joseph DeAngelo.

The guilty plea not only spared the victims and their families from the ordeal of a lengthy trial but also ensured that DeAngelo would face the consequences of his actions for the rest of his life. It served as a testament to the tireless efforts of law enforcement and the strength of the evidence against him.

Impact and Legacy

The Golden State Killer left a trail of devastation in his wake, with 13 people brutally murdered and countless victims of rape and burglary. The crimes committed by Joseph DeAngelo, also known as the Golden State Killer, spanned a decade-long crime spree that struck fear into communities across California.

The capture and conviction of Joseph DeAngelo brought some closure to the survivors and the families of the victims. After more than 40 years of living in fear, they finally saw justice served. However, the scars left by the Golden State Killer’s violent crimes will never fully heal.

The case of the Golden State Killer has had a profound impact on criminal investigations. The successful use of genetic genealogy and DNA evidence in this case highlighted the potential of these techniques in solving cold cases. It opened the door to new possibilities for law enforcement agencies and has led to the identification of numerous other suspects in unsolved crimes.

Media Coverage and Retelling

Documentaries and books have been published to delve into the details of the crimes, the extensive investigation, and the lasting effects on the survivors. These retellings aim to educate the general public about the case while shedding light on the immense power of DNA evidence and genetic genealogy in solving complex criminal mysteries.

One notable documentary that delves into the Golden State Killer case is the Unmasking the Golden State Killer series, which provides a comprehensive overview of the crimes, the exhaustive investigative process, and the impact on the victims. Through interviews with law enforcement officials, survivors, and experts in the field, this documentary offers a captivating and informative portrayal of the events surrounding the case.

Another compelling piece of media that has emerged is the book Catching the Killer: Inside the Hunt for the Golden State Killer. This gripping account takes readers on a journey through the Golden State Killer’s reign of terror, the tireless efforts of investigators, and the groundbreaking techniques that ultimately led to his capture. It delves into the intricate details of the case, providing a comprehensive understanding of the challenges faced and the triumphs achieved.

These documentaries and books serve as a means to captivate audiences and honor the victims and their families. By shedding light on the tireless work of law enforcement and the crucial role played by DNA evidence and genetic genealogy, they aim to raise awareness of the power of these tools in solving crimes and bringing justice to those affected.


The capture of the Golden State Killer through the use of DNA evidence and genetic genealogy marks a groundbreaking achievement in the field of criminal investigation. This high-profile case has showcased the remarkable power of these cutting-edge techniques in solving long-cold cases and delivering justice to the victims and their families.

The relentless pursuit of justice over four decades led to the identification of Joseph DeAngelo as the notorious Golden State Killer. By leveraging DNA evidence and genetic genealogy, investigators could create a genetic profile of the perpetrator and build a family tree of potential relatives, ultimately narrowing down the suspects and unraveling the secrets that had long remained hidden.

Joseph DeAngelo’s arrest and subsequent guilty plea have brought closure to the survivors and the families of the victims, providing some measure of solace after years of pain and uncertainty. Beyond this specific case, the success of DNA evidence and genetic genealogy in identifying the Golden State Killer has paved the way for future investigations, highlighting the transformative potential of these techniques in solving cold cases and providing justice to the victims and their families.

Wish to continue your study of this true crime case? Consider the book linked below. (Please note that this is an affiliate link. If you make a purchase I will receive a small commission at no additional expense to you).


About the Creator

Matthew Jack

My 30-year law enforcement career fuels my interest in true crime writing. My writing extends my investigative mindset, offers comprehensive case overviews, and invites you, my readers, to engage in pursuing truth and resolution.

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