The Golden State Killer and DNA

Joseph DeAngelo, 2018 mugshot, alleged Golden State Killer

Unless you’ve been living under a rock for the past few days, you already know that the Golden State Killer has, it appears, been apprehended by:

  1. Sequencing DNA from the original crime scene
  2. Uploading those results to a genealogy data base to utilize techniques currently used for unknown parent searches to suggest or identify the killer
  3. Then, to confirm that they had identified the right person, discarded DNA from the suspect was sequenced which apparently matched the original DNA from the crime scene

I say “it appears” because remember, until he’s convicted, Joseph DeAngelo is still a suspect.

I have received more messages, texts and e-mails about this one topic than any other, ever. My phone has been buzzing like an angry bee with too much caffeine for days.

Unfortunately, in many news articles, the topic suffers from dramatic over-simplification at best and significant errors at worst. This combined with lots of fear stirs a toxic brew.

In almost all cases, the author writing the article clearly didn’t understand the subject matter at hand. Many leaders in the genetic genealogy community have been asked for comment. Having had more than one situation in which I was misquoted or my quote was taken out of context, I am discussing the issue in this article, where my comments aren’t boiled down to a one sentence sound bite. I don’t want anyone making a knee-jerk reaction with partial information. This topic deserves, and must receive much more discussion in a calm, informed manner.

There is a great deal of concern, curiosity, misinformation and incorrect assumptions in the genetic genealogy community as well as the media, along with emotions running at high tide.

I think it’s important to do three things:

  1. Discuss what actually happened.
  2. Discuss how genealogy versus both unknown parent and forensic searching differs from genealogy searching.
  3. Discuss associated concerns.

The Case

The Golden State Killer has been accused of at least 12 murders, more than 50 rapes and many burglaries primarily from June 1975 through May 1986. DNA evidence was collected, but DNA testing at that time had not progressed to the point where the culprit was able to be identified by utilizing his DNA.

A lot has changed, both in terms of DNA technology and other resources available since that time.

Last week, on April 25th, Joseph DeAngelo, now in his 70s, was arrested after DNA matching implicated him as the Golden State Killer. The news is ripe with stories, but this NPR article is a good summary as are the references at that bottom of the wiki article linked above.

Initial Concerns

Initially, two questions were being asked.

  • Which genetic genealogy company “cooperated” with law enforcement?
  • Did law enforcement have a search warrant?

As it turns out, the answer is that no testing companies “cooperated” and that no  search warrant was needed.

The next question was, “How safe is my DNA?”

Let’s talk about what happened, how it was done and how it affects each of us.


I was not involved with this or any similar case in any capacity, although I have been working the past few days to ferret out what actually happened, including discussing this privately and in public forums.

However, I am familiar with the techniques used as a result of my involvement with archaeological digs and ancient DNA, and I’d like to discuss what actually happened, as best we can unravel to date.

DNA Collection

At the time of the rapes and murders committed by the Golden State Killer, one police officer froze extra samples of the evidence, just in case, for the future. That future has arrived.

In the past few years, whole genome sequencing of ancient DNA and degraded samples has become possible. Probably the most notable are the Neanderthal and Denisovan genome reconstructions, beginning in 2010, but sequencing of forensic samples has become commonplace in the past few years.

From those ancient sequences, as long ago as September 2014, whole genome sequences were being reduced to just the DNA locations supported by GedMatch and the resulting compatible files uploaded there for comparison to other testers. This was possible because the raw data files are made available to testers by testing companies, so testers can modify the files in any way they see fit without the cooperation or involvement of any lab or company.

More ancient samples were added to GedMatch in the following months, and the ancient DNA comparison feature continues to be quite popular. No one ever thought much about it, but there is absolutely no reason that same technique couldn’t be used for other samples, and indeed, now it has.

Just 13 days before the arrest of DeAngelo, another homicide was solved by DNA sequencing. A murder victim, known as Buckskin Girl, found in 1981 was identified as Marcia Lenore King.

According to the non-profit Doe project, whole genome sequencing was performed, the file reduced to a format needed for GedMatch, and the file uploaded.

Again, there was no public outcry – possibly because a victim had been identified and not a criminal suspect, and because the event was not as widely publicized. However, it’s also possible that if the Buckskin Girl’s murderer left DNA evidence on the body, that sequencing could have identified both the victim and the murderer.

The identification of Buckskin Girl, however, did spur non-public debate within the leadership of the genetic genealogy field. Little did we know that the next case would follow dramatically in just two weeks.

GedMatch Matching

GedMatch is an open data base created in 2011 by two individuals in order to facilitate open sharing of autosomal matching between people, even if they tested at different companies.

Of the DNA testing companies, at that time, only 23andMe and Family Tree DNA provided centiMorgan information, recently joined by MyHeritage. Ancestry does not provide this information to their clients, so if an Ancestry client wants to see how they match other individuals in terms of actual chromosome locations and centiMorgans, they must transfer to either Family Tree DNA, GedMatch or now, MyHeritage.

Because GedMatch, with few exceptions during periods of change, matches customers from every vendor against customers from every other vendor, at least partially, they have become the clearing house for many people, especially Ancestry customers who don’t have the chromosome comparison option natively at Ancestry.

I want to be VERY clear about what you can and cannot see and do at GedMatch.

You can see your matches by the name they have entered, which can be an alias, along with their e-mail and how you match them. You CANNOT see the information of anyone you don’t match, unless you utilize another person’s kit number to see who they match. This has always been how GedMatch functions.

GedMatch users do NOT have access to your actual DNA file – ever. They can see who they match, and if they have your kit number, they can see who you match as well. Here’s an example of my own match screen.

Note – typically when showing GedMatch screen shots, I would blur the kit numbers and names in keeping with good privacy practices. However, since the point is to show you what one can actually see, I haven’t, because the top two matches are my own kits from Ancestry and 23andMe, and the third kit is that of my deceased mother whose kit I now manage. I also want to demonstrate that truly, there is nothing frightening or threatening about the information your matches see about you.

Best Matches

From a genealogist’s perspective, your “best matches” are to known close relatives, because when you match that relative and another person, especially on the same DNA segment, it’s a good indication that you share a common ancestor further back in time.

Genealogists build “clusters” of those types of matches in order to prove a relationship to a common ancestor. This is the heart and soul of DNA matching for genealogy.

For example, someone who matches you and your first cousin, both, on the same rather large segment assuredly shares a common ancestor with you and your cousin someplace in the past. The genealogical goal, of course, is to identify that long-deceased ancestor.

For example, if you match a first cousin, you know that your most recent common ancestor is one of your two sets of grandparents. Most genealogy matches are further back in time than either first or second cousins, making the identification of the common ancestor more challenging. Discovering that common ancestor is the goal of the game – because these matches to people with the same ancestor in their tree (generally) confirm that your ancestor is accurately identified. Some matches solve long-time family mysteries and break down brick walls.

However, not all brick walls are in the past.

Adoptee and Parental Search Matching

A few years ago, genealogists attempting to find unknown parents for adoptees and people with unknown fathers noticed that there were matching patterns to be followed successfully.

With millions of people having tested today, it’s much easier than it was a few years ago to find that key match (or matches) that reveals or confirms the identity of either an ancestor or an unknown parent.

While both genealogists and unknown parent searches look for close matches, the techniques diverge at that point.

Genealogists use a first or second cousin match to move backwards in time, looking for common distant ancestors.

In unknown parent searches, the same genealogical technique is used, EXCEPT, the person doing the searching could care less about older ancestors, such as great-grandparents. They are looking for their immediate ancestors – their parents.

Therefore, when an adoptee finds that critical first cousin match, they aren’t interested in figuring out a common ancestor for genealogy, meaning going backward in time. They covet that first cousin match for the purpose of coming forward in time, meaning towards the present in order to identify parents.

If you match to someone as a first cousin, you share a common set of grandparents. You can’t tell, without additional information, which set of grandparents, but given that you do match as a first cousin, there are only two positions the match can have in your family – either the pink or blue person above. This means that either your father or mother was a sibling to your first cousin’s parent.

You either share your father’s parents with your first cousin, or your mother’s parents, but you don’t know which – at least not yet.

With that much information, it’s fairly easy to uncover the rest. After all, you only have two sets of grandparents and anyone who is your first cousin will point to one of those two sets of grandparents.

You need to figure out who else matches you AND your first cousin, and then look at the genealogy of everyone who matches in that group until you discover the name of common family members/ancestors that you recognize, meaning an ancestor on either your maternal or paternal side to confirm that your first cousin matches you on that line.

Of course, for people who know their parents, figuring out first cousins is easy and takes about 2 seconds – but not so much for adoptees. Adoptees look to see how people who match them also match each other. For example, does the same couple or ancestor appear in the trees of multiple matches? In the example below, if the tester matches all three blue people as first cousins, the name of the blue cousins’ grandparents would be the same, suggesting that the tester’s grandparents were that same couple.

Next, it’s necessary to figure out which people who descend from the common set of grandparents might be candidates to be the parent the tester is seeking. In the example below, we’ve expanded the side of the three blue first cousin matches, adding their parents’ siblings as parent candidates for our tester. Factors such as age and location at the time of conception are taken into consideration when focusing on parent candidates.

If the tester doesn’t know who their parents are, they would be VERY interested in determining ALL of the children of the grandparents of their first cousin. Because one of the children of their first cousin’s grandparents IS THEIR PARENT.

In our example above, let’s just look at one of the grandparent pairs of the blue first cousins. The first cousins know who their grandparents are. The tester does not. In this case either the father or mother of the tester is the child of the first cousin’s grandfather and grandmother. Meaning that the red mother is the female child of the grandparents, or the green father is the male child of the grandparents.

We know that the grey parents of the first cousin matches can be eliminated as the tester’s parent. If the first cousin’s parent was also the parent of the tester, then the first cousin wouldn’t be a first cousin, but would be a full or half sibling.

However, the matching first cousins’ parents have three siblings who have not DNA tested, nor have their children, shown in pink and green. One of those three siblings IS either the father or mother of the tester. Of course, if the grandparents didn’t have any female children, then the tester’s father is one of the green male children of the grandparents, and vice versa.

In the example shown below, the tester’s mother IS the female child of the grandfather/grandmother pair and has been moved into place. This would be determined either by direct testing of the pink or green people, or their descendants, or by process of elimination through DNA tests of the other siblings or utilizing other pieces of information such as age and proximity.

Some adoptees are lucky enough to test and discover that a parent has tested and is waiting for them. Sometimes an unsuspected half sibling appears. Sometimes, there is no close match and the adoptee has to do more research work, including tracking people through social media and other means to find candidate family members to DNA test or to see if they know who might have been the much-sought-after parent.

Search Techniques

This type of research work has been taking place for years, individually, through groups like DNAadoption and DNADetectives who utilize volunteer search angels, as well as by several researchers who make a living doing this type of personal search. My focus is not on adoption search cases.

No one has seemed to consider this unethical, even though some of this work, especially when a parent isn’t immediately evident, involves utilizing the DNA of the tester’s matches and their matches’ relatives, connecting the family dots through social media, specifically Facebook pages, to discover the identify of someone who may not welcome that discovery. However, like GedMatch, Facebook, while not intended for this purpose is public and is heavily utilized by adoption searchers.

Some adoption search cases end very well – with heartfelt beautiful reunions welcomed by all parties. Others not so much, potentially upending the life of the biological parent that was established after the adoption took place which leads to a rejection that devastates the adoptee. Much of the damage can be done by the search process itself, meaning that the biological parent is “outed” by the process of people working through relatives who have tested and match in various ways. Of course, they ask questions to identify the biological parent – meaning that by the time the parent is identified they have no say about their own privacy.

Once DNA is uploaded to a data base, the search techniques for biological parent searches and to identify Buckskin Girl and DeAngelo, are exactly the same.

These searches all utilize matches to others, and the matches’ trees, to move forward in time to current to search for contemporary people, not ancestors further back in time.

Back to the Golden State Killer

Ok, back to the Golden State Killer.

We have the killer’s DNA sequence from the original crime scene and the file reduced to the number of DNA locations utilized by GedMatch.

Someone, presumably one of the investigators working on the case, uploaded that file to GedMatch, which appears to be entirely permissible because the police have legal custody of that DNA sample.

Let’s say the investigator, just like a genealogist, found a first cousin match, or even more distant (read difficult) matches further back – and they did exactly what people searching for unknown parents do. The investigator eventually worked through all of the possibilities based on common matches – then looked at age, location, opportunity and factors that might exclude some candidates. In this case, because it’s a rape case with the criminal obviously a male, females would be excluded, for example.

Evidence from DNA matches to the biological sample of the Golden State Killer caused the police to focus on DeAngelo.

After DeAngelo was identified through matches as a suspect, the police obtained his discarded DNA. Discarded DNA could be anything from a coffee cup thrown away to a cigarette butt or something from the trash.

That discarded DNA was sequenced, and a few days before his arrest, uploaded to GedMatch as well. The discarded DNA apparently matched the earlier sample from the killer as “himself” and the other people that the killer matched in the same way – establishing the fact that the Golden State Killer and DeAngelo were one and the same person.

You can see that I match my own 23andme and Ancestry kits as my closest matches in the GedMatch example I showed.

In essence, what the DNA of “the killer” obtained from the crime scene did was to generate leads through matching that allowed the police to identify DeAngelo and obtain a sample of his discarded DNA in order to verify that DeAngelo was the same person as the killer. Of course, he’s still a suspect today, not yet convicted.

Cooperation or Search Warrant

The police, in this case, didn’t need to ask for anyone’s cooperation. They already had the sample from the killer, they did what hundreds of thousands of others have done and simply uploaded the file to GedMatch.

The investigators didn’t need a search warrant because they weren’t asking for anything from GedMatch not already freely given, meaning matches to anyone who has already uploaded their information.

The investigators only used that matching information to generate tips for further investigation. They repeated the entire process with the discarded DNA sample to verify the earlier results obtained with DNA from the crime scene.

It bears noting here that if DeAngelo’s DNA had NOT matched that of the killer and the other people in the same way the killer’s DNA had matched them, then the discarded DNA would have eliminated DeAngelo as a suspect.

So, no genealogy testing company had to cooperate with anyone, nor was a search warrant necessary.

What’s the Rub?

We now have a monster about to be brought to justice. Two weeks earlier, Buckskin Girl, a murder victim, was identified and the family will finally have closure, 37 years later. Both of these are unquestionably wonderful outcomes.

So why are some people upset?

In some cases, people are simply confused about the process involved, and they will be relieved when they understand what actually happened – that their DNA was not “handed over” to anyone.

Some people have broader reaching concerns about privacy.

It appears that the word “police” combined with the word “criminal” caused a great deal of fear and trepidation, especially since a suspect was identified this time, not a victim and not someone’s biological parents.

Some people don’t want their DNA utilized to identify a family member, no matter what that person has done. And yes, that’s very nearly an exact quote from an e-mail I received.

Others are simply uncomfortable with their DNA being used in any kind of a potential criminal setting – even to identify a victim like Buckskin Girl.

One person says that it just makes her feel “creepy.” Oddly enough, that’s how I feel about Facebook now.

If you think it’s fine for adoptees to identify parents using these techniques, but you don’t think it’s alright for victims or criminals to be identified, I’d like to ask you to consider the following scenario.

A underage female is raped and becomes pregnant. She reports the rape to police at the time. She opts to have the child instead of having an abortion, and the child is placed for adoption. The rapist is never caught, and the young woman goes on to establish a new life and marry, not telling her husband or children born to the marriage about the rape, or the child placed for adoption. The expectation of the mother at that time was certainly that “no one would ever know,” whether those words were ever in an adoption contract or not. The fact that adoptions were (and still remain in many places) closed speaks to the expectations set for the mother.

Years pass, and today the adopted child, now an adult, tests. Both of the adoptee’s biological parents are identified through matches to relatives of the adoptee’s parents who have tested, such as first cousins in our earlier example. The adoptees parents themselves did not test.

Results were:

  • The life of the mother, a victim who did nothing wrong or illegal, and who chose to give the child life, is upended through the process of being identified.
  • The father who is a rapist, a criminal, is also identified.
  • The adoptee is subsequently very unhappy with both results for different reasons, but cannot press “undo.”

I’m NOT inferring that these data bases shouldn’t be used for identifying parents. I AM saying that we need to consider that the techniques for identifying parents, victims and criminals are the same. The outcomes are not always positive in parent searches AND these areas are or can be incredibly intertwined. Unraveling or prohibiting one effectively prohibits others. How do we treat everyone fairly and how are those rules, whatever they might be, enforced, and by whom?

In other words, how do we “do no harm”? After all, this started out to be genealogy, a fun hobby, and has now progressed gradually through a slow crawl to something else. Here we sit today.


In the example rape case above, neither the biological mother nor the father had tested, but their family members had – just like in the Buckskin Girl and the Golden State Killer cases.

Today, relative to the Golden State Killer, people are upset because the database, GedMatch, into which they uploaded their DNA file for genealogy was used for other purposes – specifically to apprehend the Golden State Killer. They feel that isn’t the purpose for which they uploaded their DNA.

Any one of us could have been one of the matches to the Golden State Killer and some people obviously were. It bears repeating here that no one’s DNA or results were “handed over,” and the only people affected in any way was someone that matched DeAngelo, and probably then only the closest matches. Many time people’s trees are utilized and their cousins never contact them, so it’s certainly possible that people who match DeAngelo have no idea still to this day.

The usage evolution for GedMatch from genealogy to other functions has been a slippery slope, although clearly no one realized at the time, when several years ago uploads began with modified ancient sample kits. Later, people began to use the GedMatch database (among others) to identify biological parents, then victims and now criminals.

Other people feel that searching for parents is genealogy, but identifying criminals is not – even though the search techniques are exactly the same. In our rape example, the mother who was a victim was identified and the criminal rapist father was identified as well by the same DNA test. The tester’s intent was only to reveal their biological parents – hoping for a loving, tear-filled reunion. That’s not what happened. The process of finding their parents also revealed the associated circumstances.

You can’t separate these usages into separate “boxes” anymore, because they overlap in unexpected says. That rape case wasn’t hypothetical.

I have absolutely no sympathy for the rapist, in fact, quite the opposite – but I feel incredibly bad for the young mother who has now been twice victimized. First by the rapist and second by the process used to track her, through relatives who began asking lots of difficult questions.

Last fall, in a Facebook group I follow, I was utterly horrified to see someone post that in the adoption cases she works, she encourages the adoptee, when they feel they are “close” to identifying a parent, to send registered letters to all of the family members, asking them to test, hoping that those who aren’t the parent quickly test to absolve themselves and as a way to flush the parent out.

It’s Not Just Your DNA

In either case, the DNA of the RELATIVES of the person being sought, be it a parent, a victim or a criminal, is what is used to find or identify the desired person. People who have uploaded to GedMatch are now concerned that they might be that relative whose DNA is used in a way they did not originally anticipate. They are right, and not just about this particular criminal case – but about the many types of usages other than strictly genealogical that looks backwards in time.

Perhaps the people who uploaded never thought about the fact that their DNA is/was being used for adoption or missing parent searches – or perhaps they are supportive of that activity. Maybe they thought that identifying victims, such as Buckskin Girl was a great use of the data base by investigators. Maybe they never thought about the fact that searching for criminals who leave DNA specimens behind uses exactly the same research and matching techniques as adoptees’ parent searched.  Perhaps no one stopped to think  that the same search can identify both parents, a victim and a criminal at the same time.

Maybe they were naïve and never thought about it at all or didn’t read the GedMatch statement that said (and says):

In today’s world, there are real dangers of identity theft, credit fraud, etc. We try to strike a balance between these conflicting realities and the need to share information with other users. In the end, if you require absolute privacy and security, we must ask that you do not upload your data to GEDmatch. If you already have it here, please delete it.

I can’t tell you how many of the posts and e-mails I’ve seen about this topic include the word “assume,” and we all know about assume, right?

Maybe, like me, some people have thought about that potential situation and want criminals, regardless of whether they are relatives or not off the streets. If they are relatives, so much the better, keeping my own family safer.

Some people may have been uploading their relatives’ DNA samples to GedMatch or any other site other than where the relative originally tested without the relative’s permission. If that’s the case, the person either needs to obtain permission, pronto, or delete the person’s DNA they uploaded without permission.

GedMatch’s Statement

GedMatch has posted the following statement.

Testing in the Future

Another concern voiced this week is that people, especially relatives that we want to test, will be much more reticent to test in the future if they think the police can “take” or “access” their DNA. That’s probably true, so we need to be prepared to explain what actually happened, and how, to eliminate misconceptions

However, it is true that DNA in these databases has been and is being used for things other than genealogy. This is also the purpose of informed consent – with an emphasis on informed. Bottom line – the cat’s out of the bag now. Perhaps these incidents together, meaning parent searches, the identification of Buckskin Girl and the arrest of the Golden State Killer, will bring home the warning that was previously noted on GedMatch.

If you’re not comfortable – don’t upload. This also means that people MUST STOP simply telling other people to upload to GedMatch as a cure-all for everything that ails genealogists. If you are making the recommendation, you also bear the responsibility for full disclosure or at least a caveat statement.

“GedMatch is great for genealogy matching to each other across vendor platforms <or words of your choosing>. It’s also used for adoptees searching for their parents, was used to identify Buckskin Girl and played an important role in the apprehension of the Golden State Killer.”

As a result, GedMatch now provides a way to remove your entire account, if you so wish. GedMatch needed to do that for GDPR anyway. As long as we are on the topic, GDPR, which goes into effect on May 25th tightens privacy significantly for any vendor or company that includes records of any UK/EU resident. You can read about that in my articles here and here.

Every (major) testing company, along with GedMatch provides the option of removing your DNA results if you are so inclined.

As for people being hesitant to test, certainly some already were and some will be. But there will also be others that only first heard about genetic genealogy this past week and this notoriety won’t deter them one bit. Some people will actively choose to participate, knowing that they can later change their mind if they so choose. I notice the GedMatch site has been busier than ever.

In summary, the police did not “take” or even ask for anyone’s DNA. They simply uploaded the DNA results of a criminal, taken from the crime scene, and looked at the matches generated in order to make an ID, at which time they obtained the DNA of the suspect which matched the DNA from the crime scene.

Just like genetic genealogy, DNA without supporting evidence won’t be much good, but now they have someone identified to work with, collecting other evidence. Where was he? Does the DNA at multiple scenes match his? I would think in terms of a prosecution that these matches and arrest is only the beginning, not the end of the process.

Given that none of the major genealogy companies cooperate with law enforcement without a search warrant, it’s a WHOLE LOT easier to obtain your discarded DNA than to obtain a search warrant. Furthermore, there is no chain of custody with DNA from a genealogy data base, but there certainly is from a rape and from a discarded cup. If the DNA of the criminal from the scene, and the suspect’s DNA from a discarded item match as the same person, that’s pretty conclusive and damning evidence.

Of course, fear begets fear and the old questions of government access and other issues bubble up again.

Another question I’ve received is about whether the usage of GedMatch for the Golden State Killer case opens the door for DNA to be obtained by insurance companies. First, you’d have to test and upload something. There is nothing to “get” if you don’t – and the insurance company would need a search warrant (and probable cause of a crime) to retrieve your DNA from any testing company.

GINA legislation protects American’s today from discrimination when obtaining health insurance, but it doesn’t extend to life and other types of insurance. However, when I applied for life insurance some years ago, they took a blood sample and if I wanted life insurance, I had to authorize whatever it was they wanted to test in that sample. I’d wager that today, they would run a DNA test in addition to checking for other health indicators. No GedMatch or testing company is needed or desired – in fact – an insurance company requires chain of custody which is why they send someone to your house to draw your blood.

What To Do?

What you do with your DNA sample is entirely up to you. Everyone will make their own decision based on their own circumstances and preferences.

Some people have removed their DNA from the various databases and in essence, have stopped participating in genetic genealogy.

Some have made their kits at GedMatch either research or private. Research means that you can run the kit and see matches, but others can’t see you. That certainly defeats the spirit of collaborative genealogy.

Some people have evaluated the evidence at hand and have made the decision to continue as normal – just more aware of other uses that can, have and may occur.

This story and others similar will continue to arise and unravel, and many questions will likely be asked and hotly debated over the next many months and years, both within and outside of this community. I would not be surprised to see legislation of some type follow – which has been one of the biggest fears within the genetic genealogy community for years. Legislation by people unfamiliar with the topic at hand will likely be overreaching and extremely restrictive. Let’s hope I’m wrong.

Like many others, I’m concerned that the genetic genealogy field will become a victim of its own success. I hope that doesn’t happen, but at this point, the cow has left the barn and that door really can’t be effectively shut. All we can do is to be transparent, make informed choices, assure that we have the consent of anyone whose kit we manage and to advocate for sanity.

My Decision

I’ve made my personal decision and my thought process worked like this:

  1. I haven’t done anything that I need to worry about.
  2. If a family member does something they need to be arrested for, I hope my DNA helps.
  3. If I were the family of the victims, I would want them identified AND their murderer/rapist put away forever. (Disclosure, I have had a family member raped and a different family member murdered.)
  4. As a citizen, I want criminals such as rapists and murderers identified and removed from society through any legal means possible.
  5. DNA testing also exonerates people who were wrongfully convicted through advocacy groups like the Innocence Project.
  6. DNA eliminates potential criminal candidates as well as pointing the finger directly at others.
  7. Using the techniques utilized for unknown parent searches, an identification is seldom made as a result of ONE match only, unless it’s immediate family. Therefore, if you remove your own DNA from the data base(s) for matching, your cousin and their cousins are still there – so your criminal family member’s goose is still cooked. It might just take a little longer in the stew pot.

My DNA stays online and I continue to support all of the major DNA testing companies that provide matching and accept transfers, including GedMatch.



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144 thoughts on “The Golden State Killer and DNA

      • The Mercury news team also has done a good job.
        They stuck to good articles built on facts. Some others with much greater resources included quotes that appeared to state or infer things that later were shown to have been irrelevant, misleading or incorrect.
        Good on you, Mercury!

  1. I’m absolutely thrilled that they got him. I don’t care if public DNA is used. If you’re a criminal prepare to be revealed. And if you’re not a criminal who cares? Just the paranoids who think Big Brother is out to get them, as if they are so important.

  2. So, the dna from the crime/s and the dna from the suspect were “processed” by the labs of law enforcement?

    I wonder if they would have a different procedure for uploading to Gedmatch and what the prefix of the kit would be? I.e., if that is a prefix we have never seen in our matchlist, that must be the kit?. But, they have probably deleted that kit by now. LOL

    Roberta, thank you. I agree with eveything you have expressed. When someone commits a crime, they should be held accountable, relative, or not a relative

    The public safety of our citizens is paramount and takes precedence. Those who are paranoid about privacy have the option of deleting their dna accounts. Nuff said.

  3. Another incredibly informative and helpful article, Roberta! Thanks for being there to explain and clarify things for us. Cousin Jim

  4. Roberta I believe that whoever uploaded the suspects DNA did not have his permission and did not have a court order. If I upload my cousins DNA I seek permission and do not do so by misrepresenting who I am. There is a difference. My problem is with protocol and procedure. The TOS were not abided by if the person uploading did not have the subject’s permission. IN the absence of such permission (whether the DNA was legally obtained or not) then a court and transparency should have been practiced and it appears it was not as GEDMATCH was unaware. I think this is a sticky wicket and I want protocols and procedures in place to protect all. I believe that searches of this sort do engage privacy laws that have no been fleshed out in the courts.

    It is my personal belief that GEDMATCH was used because it lacks the kind of legal department that other companies employ. I do not consider GEDMATCH public anymore than Ancestry is public. They are both privately owned and they offer a service…for free or by subscription but its rules were not abided by. And law enforcement breaking the rules is where I draw a line. Respectfully, Kelly

    • Anything left at a crime scene by a perpetrator has NO protection in the law against being used for the identification or prosecution of the criminal. Zero.
      For example, fingerprints. If you are trying to argue that the police violated GedMatch rules of submission, even then the supposed offense would be civil and contractual in nature, not any violation of the criminals’ supposed right to privacy.
      That would be up to GedMatch to complain about to the proper authorities, and that’s not going to happen. The GedMatch Database is about as public as it gets. Free, and available to all, and by far the best DNA resource on the planet!!

      • Barry, what about discarded DNA? Suppose that an agency like the police puts an entire neighborhood under surveillance, obtains discarded DNA from many of its inhabitants without their knowledge. If that is legal, is it also legal for them to:

        1. Add all the DNA profiles from the discarded DNA to their own databases, which are routinely compared against crime scene evidence?

        2. Upload all of those profiles to GEDmatch under various aliases?

      • Anyone can fish through their neighbor’s trash to assemble a profile of who their neighbor is. Ethics and neighborly relations aside, there is probably no actual law against doing that. But why would anyone want to do that to their neighbors? With petty issues, it is best to “live and let live”.

        When a capital crime is suspected the police can and WILL do it, to identify a suspect.

        The important part here is that once the suspect becomes a suspect, (or as the more kindly phrase now used is that of being called “a person of interest”) it doesn’t matter how he was discovered. In his being a serial rapist and murderer there is already a ton of other material evidence that has been accumulated against him over many years That still pertains even if and when ALL the DNA methodology and evidence might be disallowed and thrown out by a court of law.

        Good genealogists are actually history detectives – they pursue the truth no matter where the evidence or facts may lead – “the good, the bad and the ugly”. So why would anyone be against the discovery of whatever it is that happened?

    • Blaine Bettinger has posted that he has been helping GEDmatch. Blaine is an attorney specializing in this field.

    • The police did nothing wrong. They took the victims DNA with their permission. They acquired the suspects DNA in the public domain so permission wasn’t needed.

    • @wheatonwood – Gedmatch was used because it is the ONLY company that gathers data from the other testing companies. Gedmatch is NOT a testing company. Gedmatch is an apple, testing companies are oranges.

      It has not been established that law enforcement broke any laws. In fact, we should be applauding them.

  5. Well said, Roberta. Thank you for the easy to understand explanation of the process used to find the suspect in the California case. I’ve been asked by several family members and friends how something like this will affect my genealogy research. Now I have an excellent source that I will share to put their minds at ease.
    Your faithful reader,
    Eileen Miller

  6. Excellent Well Written! Bravo to the Author !(don’t see authors name included in the post)
    May i share with others?

  7. There are people who still think that DNA is fake. I am a genealogist and while searching for my father in laws ancestry, he rebelled against my efforts. His father had spent time in an insane asylum after being in prison and juvenile prison before 1950s. Shame from his childhood, that involved domestic abuses, father being paranoid, family using an alias, then abandonment. Neighbors knew the situation and shunned the family and the single parent supporting the family, and my father in law being forced into being the man of the house at age 11, or so, left him traumatized. Add to that, surviving the Great Depression, WWII, and being 2nd generation immigrant of German Jews. He was very eager to rewrite his life story which my research would crash. When I found photos, genealogy supported by census data and info from his large group of maternal side relatives – he said my research was all wrong.

  8. Roberta, well done, as usual!

    I would like to comment on what you said about insurance companies. I remember receiving a statement from my health insurance company and seeing “NO CHARGE” next to a line item that definitely said “DNA”. It was right around the time when we became aware of the discovery of a “breast cancer” gene. Thinking about where I was living, etc. I would put my receipt of that statement somewhere between the year 2000 and 2006. A month or so prior to receiving this statement I had a routine blood draw for my annual check-up. Clearly, my DNA was tested without my knowledge, although the fine print in my contract probably gave my consent. There were no results shared with me and I find it hard to believe the insurance company simply threw that information away. I think it’s naive for anyone who has had blood drawn in the last 20 years to think they have never been DNA tested for something! I also think it’s naive to think the DNA was subsequently trashed. This company was and still is one of the largest in the nation. I’m not saying there is any reason to believe DNA collected in this manner would be available for scrutiny by law enforcement or genealogical researchers. I’m just pointing out that those who say they will never have their DNA tested because of privacy concerns, may well have already had their privacy invaded, and they consented to it!

  9. Thanks, Roberta, that was a good analysis. The similarities between this case and adoption searches is being overlooked, I think.

  10. Thanks,

    That’s interesting to me as I was in Walter Reed (the old one) and given a blood workup,by a person who spoke bad English, and next time I went I was read all kinds of things which were not my blood findings. I was surprised. Walter Reed is quality and I love their work with injured Americans, as I am retired military. We got it right the next time.

    Some how my blood got crossed up with someone else which got me thinking. What controls are really out there to protect Americans from dangerous people doing nasty things to their blood? I’m 80 and and that was nearly a decade ago. But all of us older types get blood work ups, and some as often as monthly. ( I have, and up to four blood samples is the usual.)

    Where does this blood go? Perhaps some is resold, and some is simply destroyed, or given for research. No one I am aware of seems to follow it to the end destination.

    For one, people with serious DNA problems or diseases ought to be identified, according to their problems and their blood donated for research. For example, I have some inherited problems and 23&me thanked me for my contributions to the Parkinson’s effort. I believe a jump in knowledge is possible by means of the latest DNA testing methods which we can all contribute to. I also have CIDP and the treatments came from blood origins.

  11. My guess: The actual DNA tests that will be used as evidence in the current criminal proceeding will be (1) those from the crime scenes, and (2) a sample obtained legally from the suspect after his arrest, which would have the effect of confirming and verifying the “discarded object” sample that was used as probable cause to obtain the arrest warrant, and which would clearly be the best possible evidence that the accused is in fact the perpetrator. Once those two samples are admitted as evidence, the long story of how the accused was identified, although griping (and including the GEDmatch episode), is largely irrelevant to the case and is not itself needed as “evidence”. Put another way, once the identity is clinched with DNA samples admissible as evidence, all the genealogies and family trees are irrelevant to the question of guilt. Also, law enforcement would not use GEDmatch or any similar consumer-oriented service to compare two DNA samples it already has — that would be done “in house” by some acceptably certified forensic lab.

  12. That was an awesome article!! Thank you. Me personally, I did an mtDNA test to answer questions about my mother’s ancestry. It was different than I supposed. I found your site because I was ignorant about what the mtDNA result meant. I knew my haplog group but didn’t understand I would have to build a tree to learn who are my “in my tree” relatives. I’m not interested in doing this.

    What surprises me is the extent people feel they “own” their lineage: one goes back 5 generations and you have 32 direct in line ancestors. Given recombinant DNA and 1/32 “relation” it doesn’t feel personal to me. What does feel personal are gene pool ideas, the movements of whole peoples, which my haplog group indicates.

    The daughters of Joe DeAngelo, everyone who knows them knows who their dad really is. Now that is hard. But then, monster serial killers, what can one say but prayers. The daughters aren’t their dad, and the current info about the “why” of people like DeAngelo doesn’t implicate the daughters genes, they carry monster making genes. The real why of DeAngelo likely lies in the nature/nurture argument which is now link to how the environment turns on and off certain genes throughout one’s life from zygote to death.

    It is chilling to think that DeAngelo aged out of being a serial killer. It is chilling to think DeAngelo wasn’t psychotic but psychopath who stalked his victims, killed 12 etc. I agree with you. Catching criminals of this order – GOOD. There are uncaught rapists and murders who will NOW worry, until they are caught, about their DNA trail. If this is all the punishment they get, it is better than none.

    • Thank you for your words. I was conceived in rape by a serial rapist and I’ve lived for decades hearing people suggest that somehow I carry a rapist gene, and that children like me are “tainting the gene pool.”

  13. Hi,

    It’s my understanding that the autosomal DNA studies often display cousins with cmorgan strings, which overlap. Some, even the short ones over lap. In time, many of these may well over lap into long cmorgan strings which can be given a UID, and determined just who contributed that string. Genealogists would love this. Perhaps giving us back our ancestors now believed lost to time.

    Where does this idea stand at this time? It surely seems to raise the dead from the graves. KBP

  14. Thank you Roberta for another well-reasoned and informative article. I was unaware law enforcement DNA samples could be manipulated into a format acceptable as an upload to GEDmatch.

    And I whole-heartedly agree with each of your decisions points. I’d go so far as volunteering my DNA for any worthwhile study or research, although I take issue with 23andMe’s possibly clandestine use of our DNA samples for profitable medical research without full disclosure and transparency. The issue with the Henrietta Lacks case was the absence of consent and disclosure; otherwise, her unknowing contribution to medical research has been repeatedly recognized and honored.

  15. Well done and comprehensive assessment! I think we all have different thresholds for privacy that we need to consider thoughtfully.

  16. I found the identity of my biological father through DNA and family trees. He had abducted my birth mother at knifepoint and was suspected to be a serial rapist. Many others for my organization Save The 1 have found their rapist fathers through this means as well. I think the Golden State Killer case is only the beginning of crimes being solved this way. Only the criminals should be concerned.

  17. Roberta, thank you for what is easily the best of the various blogs I’ve read on this. One thing I disagree with. You say ” You CANNOT see the information of anyone you don’t match, unless you utilize another person’s kit number to see who they match.” This is not true. I can search Gedmatch just using your email address, and if you have a tree there I can find your kit knowing (or guessing) any name in your tree. Once I have your kit number I can see who you match, and your ethnicity estimates etc., even if I have not uploaded my own DNA. But as you say there is no way to access anyone’s actual DNA sequence.

    • You can, but you have to find my kit number to do that. Without someone’s kit number, you can’t view their matches. And you also have to register as a user of the site before you can do anything.

    • A work-around for the email entree into GEDmatch is to create an email that you never use anywhere else. I haven’t done that myself, though.

      • Some do. Some of my DNA cousins have a different email address for each DNA lab they have used and another for GEDmatch.

  18. I’ve arrived at the same conclusions Roberta discussed. I’ve talked to two of the people who tested for me, with calls in to others. My uncle told me that he hadn’t done anything like that and wasn’t worried about it.  I’m expecting the others to feel the same way, but will check in to be sure. Velma

  19. Well done you, a wonderfully clear explanation and many points covered to make better understanding available to a lot more people. Some people are just too quick to talk about subjects they know nothing about and turn something that is a wonderful example of the technology of the times we live in and has already made amazing advances in health and other aspects of many peoples lives, into something malicious to gossip about and help spread fear among people who just don’t understand, because they lack the background knowledge. Instead of being positive and praising police for doing such a great job of by trying to get someone dangerous, who caused so much damage and fear in the past aprehended and accountable. Also identifying murder victims and putting another Jane or John Doe to rest, I am sure many families who have missing members would rather know they were accounted for now rather than just another mystery on the family tree in the future.

  20. Agree with everything you said in your “Decision Points” and thank you for shining a light on the specific facts of the DNA procedures used in this case. Your knowledge and commonsense analysis makes this article particularly valuable and I hope the Court of Law that Mr. DeAngelo is eventually tried in (or the prosecutor) will see fit to have every juror receive a copy BEFORE the start of the trial so that they can be well informed on the subject of DNA testing etc. to assist them.
    I am leading a DNA discussion group tomorrow and plan to share this and your GDPR article with them if I may.

  21. Thank you so much for explaining! I’m a tad bit of a slow learner in the tech field, so I eagerly read all I can get my eyes on! I am learning a lot, albeit slowly! I saw my own mothers life enriched by finding out who her biological dad was when she was 72, and although he had already passed away, she was able to have a wonderfully relationship with her brother for 15 years till he passed away, then I lost her 2 years ago. I am so happy that I was able to help brighten up her twilight years! I also have a son who is a policeman, so I can see it positively from 2 angles now! Great explaining for people like Me! Thank you again!

  22. Excellent article. I hope more pages/sites/newspapers use your post.
    I deal with illogical conspiracy family members, who dread the Net n DNA. No matter how many times you explain, its never going to get thru. They are happy to wallow in ignorance.
    In regards to Health Insurance, its a rip off. I hope the whole industry collapses. I have worked in the Medical field and have had to deal with utterly shameful insurance bullcrap. Its completely sane to believe they would use dna against their customers.
    I recently seen an oath Genetic Genealogist agree to. I would be willing to click okay to all of them, for GedMatch, or other sites. I think some people have to be walked thru these points to fully understand what they are doing.
    I have wanted a NamUs, Missing people, Doe’s, Rape Kit backlog using DNA & Genealogy Volunteer system setup. Its obvious that police need help. And there are so many of us willing to help.
    I am soo good with my DNA being able to catch these monsters. I hope everyone can get on the same page with that sentiment. 🙂

    • ivygeni on April 30, 2018 at 8:03 pm said:
      Excellent article. I hope more pages/sites/newspapers use your post.
      I deal with illogical conspiracy family members, who dread the Net n DNA. No matter how many times you explain, its never going to get thru. They are happy to wallow in ignorance.
      In regards to Health Insurance, its a rip off. I hope the whole industry collapses. I have worked in the Medical field and have had to deal with utterly shameful insurance bullcrap. Its completely sane to believe they would use dna against their customers.

      ALL insurance is a ripoff. How did Warren Buffet get so immensely wealthy in two decades? GEICO.

      With any insurance you are betting against an insurance company that an event WILL happen and they are betting you that it WON’T happen. The odds are always in their favor. That’s what the insurance business is, and that’s how they stay in business. You need to have a catastrophic event such as an accident or a death or to collect whatever the insurance company decides to give you, to avoid having you bringing a lawsuit.

      And then there is MANDATORY insurance, imposed by government. Think about mandatory car insurance. All states now have it. Think about Mr. Buffet’s company, AKA GEICO. Then think about government and the relationship between the insurance industry and our government. Also think about mandatory vs, voluntary participation when having vs.wanting to buy insurance. Do we still have any choice?

      Can you say NO? If you can’t say NO to buying any form of insurance, then why not?

  23. Thank you, Roberta, for your lucid post. I have shared it with my family members who have tested at the various DNA companies.

  24. Roberta, thanks so much for your well-thought out and reasoned post on this issue. You are indeed to voice of reason, providing clarity in the face of confusion, misinformation, and speculation.

    One thing, though: did you intend to have some other graphics in this post? I’m thinking of the section “Adoptee and Parental Search Matching,” where you have several mentions of “example above” and/or “example below,” mentioning colors, etc. I found it a bit hard to follow, and it seemed that you meant to use an image to illustrate what was meant in those paragraphs.
    Thank you.

    • There are graphics in the article. Are you not seeing them at all? Are you looking at the e-mail version, or the web-based version. Sometimes the graphics aren’t in the e-mails, so look online if you’re referring to the e-mailed version.

      • I was using my desktop computer. The only graphics in the article that I see are: the photo of the killer, the excerpt of your GEDmatch matches (you, you & your mother), and the GEDmatch posted statement. Are those all of them?

      • Last one – I had been using Safari, which usually has no problems with your blog. I tried using Firefox, and did see four more images, comparison charts. I wonder why they didn’t show in Safari? But, I’ll make sure to check in another browser next time. Thank you.

  25. Brilliant article, which clearly explains so many complex issues. Thank you. I will happily keep my DNA online, and now fully understand my motivations for doing so.

  26. Roberta, this is a wonderful article that explains the basic information that a person must know in order to start a DNA Family research project. It also clearly explains that GEDmatch had nothing to do with finding this criminal. I have used this very same method to help several of my adoptee cousins find parents. I’m certainly not a DNA authority but thanks to you and others, I know a little about how it works and I learn more everyday.
    Thanks so much for helping us.
    Marilyn Burnett Garner

  27. As usual, Roberta, I totally agree with your article. Thanks for all your educational articles.

  28. Amen! My thoughts exactly, Roberta. I had heard, like Ann that they worked it back from early 1800’s to viable suspects & ruling out one fellow in Oregon. It was good meeting you at Rootstech at FamilyTreeDNA booth.

  29. Thank you for writing this, Roberta! You’re getting the facts out there in a way we can understand them, and help others to make better informed decisions. I’ve seen a lot of misinformation and speculation flying around! Your voice of reason is reassuring. I think we should try to think of these investigators as having worked on their computers, identifying patterns and relationships, just as they might have done in any other case!

  30. Thankyou so much for your usual well-reasoned, dispassionate article. I always look forward to your writing and find it worthwhile. You are a gift!

  31. Excellent! This reminds me of Native American author Louise Erdrich’s comment that it wasn’t hers to give when asked if she would do DNA testing. Though frustrating for me personally as a descendant of essentially unknown Native Americans, I understand and respect her perspective.

  32. One aspect of DNA testing I had never considered before is finding missing persons and also testing in case you become a missing person.
    In the first case, dna testing should be considered by anyone who has a family member missing, especially a child snatched at a young age who might not remember his name or names of family, where he lived, etc.
    In the second case, if you have a raw data file available to family members, and have it uploaded to GEDmatch, couldn’t that be used to help authorities locate you, if you are the one who is missing because of an accident, illness, or foul play?

    What about having children tested so dna files will be available if needed. Children cannot actually consent for themselves, but would have the option of removing their dna data files when they reach adulthood.

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