How DNA led to the elusive 'Golden State Killer'

April 27, 2018
Credit: CC0 Public Domain

Detectives in California used DNA left at crime scenes, combined with genetic information from a relative who joined an online genealogy service, to catch an alleged rapist and murderer who eluded authorities for four decades.

The arrest this week of 72-year-old Joseph James DeAngelo—believed to be the "Golden State Killer" responsible for 12 murders and more than 50 rapes in the 1970s and 1980s—was hailed as a victory for cutting-edge science and old-fashioned detective work.

"The answer was, and always was going to be, in the DNA," said Sacramento County District Attorney Anne Marie Schubert.

Here's how it unfolded.

Crime scene DNA

Schubert opened a cold case investigation into the Golden State Killer two years ago, according to The New York Times.

Investigators started with DNA samples from crime scenes that were in storage to build a genetic profile of the suspected attacker, which they then uploaded into an online genealogy database to see if they could find a match.

A Lake Worth, Florida-based company called GEDMatch acknowledged on Friday that its database "was used to help identify the Golden State Killer... although we were not approached by law enforcement or anyone else about this case or about the DNA."

The company warned customers in a statement that even though the site was intended for genealogical research, possible uses of their DNA include "identification of relatives that have committed crimes or were victims of crimes," and that they should delete their profiles if they had any concerns.

Although DeAngelo himself had not sent his own DNA to GEDMatch, at least one distant relative of his had done so, and possibly more.

GEDMatch is a website that "pools raw genetic profiles that people share publicly," Paul Holes, a retired district attorney inspector, told the East Bay Times.

"No court order was needed to access that site's large database of genetic blueprints."

Larger companies including Ancestry.com and 23andMe denied any link to the investigation and said they had not given any customer data to law enforcement officials.

Online family trees

People who are related share chunks of identical DNA, which is interspersed with sections of different DNA.

Identifying these shared patterns can point investigators to people who are distant or close kin, depending on the extent of the match.

The crime lab began exploring online family trees that appeared to mirror the suspect's DNA profile.

Then, they hunted for clues about various individuals in those families, to see if they were possible suspects.

On April 19, detectives decided that DeAngelo might be the one because a number of factors aligned: the DNA, his age, and the fact that he lived in the area where the crimes occurred.

Investigators set up surveillance in the tree-lined suburb where DeAngelo lived.

Then, Schubert said, "abandoned" DNA samples were acquired from him.

Officials have not said what was used, but it could have been a soda can, a hairbrush, or anything containing DeAngelo's saliva, hair or blood.

"You leave your DNA in a place that is a public domain," she said.

This allowed experts to compare the newly collected sample to the old DNA from the scene, and it was a match to more than 10 of the murders.

The sample provided "overwhelming evidence that it was him," Schubert said, according to the Sacramento Bee.

'Astronomical evidence'

Schubert asked the sheriff's office to collect a second sample, to be sure. So they did.

"The second sample was astronomical evidence that it was him," she said.

DeAngelo was arrested outside his home Tuesday and charged with murdering two people in 1978 in Rancho Cordova, California.

He is expected to face more charges.

"This was a true convergence of emerging technology and dogged determination by detectives," Sacramento County Sheriff Scott Jones said.

Explore further: Genealogy site didn't know it was used to seek serial killer

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Mark Thomas
1 / 5 (1) Apr 28, 2018
"Officials have not said what was used, but it could have been a soda can, a hairbrush, or anything containing DeAngelo's saliva, hair or blood."

"You leave your DNA in a place that is a public domain (and it is 'abandoned')" said Sacramento County District Attorney Anne Marie Schubert.

This is a good example of a hard case making bad law. We are all pleased they caught the "Golden State Killer," but people shed cells with DNA constantly. The District Attorney here has concluded you have no right to privacy in your DNA if you lose a hair or cell in public. If they can collect it, they can use it for any purpose they want. This is a clear invasion of privacy enabled by modern technology. The 4th Amendment was intended to protect us against such invasions of privacy, but there is no money defending the 4th amendment.
Shakescene21
5 / 5 (2) Apr 28, 2018
There was no violation of the 4th Amendment, which states:

"The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

No person or item was seized by the government. DeAngelo left some hair or saliva behind which detectives collected and compared with evidence collected from murder/rape scenes. I'm sure that courts will rule that this was not an "unreasonable search and seizure". If DeAngelo had been innocent this DNA data could have exonerated him.
Mark Thomas
1 / 5 (1) Apr 28, 2018
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures


Shakescene21, so you would conclude if you go out in public it is reasonable to conclude you gave up all your DNA information forever?! That is extremely unreasonable. Shakescene21, suppose an employer refuses to hire you based on a perceived weakness in your DNA. It could be anything such as genes associated with an increased chance of cancer, lower intelligence, or even disobedience to authority. Are you sure you want to give up all that information because you made a trip to your local burger joint? The 4th amendment was designed to protect people from such incredibly invasive acts.
Shakescene21
not rated yet Apr 28, 2018
Mark Thomas, the 4th Amendment refers to the rights of the citizens relative to the government, not to citizens relative to each other. So your example of an employer using DNA (perhaps left behind after an interview) who then decides not to hire a person based on genetic analysis of this DNA, is NOT a 4th Amendment issue. This issue can be properly addressed through laws, at the Federal or State level, hopefully after careful study and debate.

By the way, this discussion is about law rather than science, and can be better discussed on some other forum.
Mark Thomas
not rated yet Apr 28, 2018
Shakescene21, the Sacramento County District Attorney is part of our government. Since the DA's office has declared open season on our "abandoned" DNA, what is to prevent the government from using and providing that "abandoned" information to anybody they want, including corporate interests? As this case shows, crime-fighting would be greatly enhanced if the government sampled the DNA of every man, woman and child in the U.S. and beyond. Maybe get the NSA to do it, they are masters of invasion of privacy on a massive scale. Corporations could use the DNA to filter out the genetically "undesirable."

"They that can give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety." Ben Franklin

https://en.wikiqu...Franklin

Mark Thomas
not rated yet Apr 28, 2018
That the U.S. government can declare any of the publiclly and constantly shed DNA they can get their hands on as "abandoned" and use that against people to imprison them violates the letter and especially the spirit of the 4th amendment.

As I wrote above, hard cases make bad law.

Funny how the only constitutional amendment defended by Republicans is the one favored by its political donors. The 2nd amendment is misinterpreted and sacrosanct while the 4th amendment is inconvenient and therefore ignored, because that is where the donor money is.
Da Schneib
not rated yet Apr 28, 2018
@Mark, the old classic is they get you in the interrogation room and give you a glass of water on which you leave your fingerprints. There's no difference in principle here.

What's disturbing is the use of the DNA data in the database; however, since all the people who gave that data apparently agreed to make it public, I'm not sure there's an issue there either.
Shakescene21
not rated yet Apr 28, 2018
I'm a long-time genealogist and my Y-DNA data is publicly available on the FTDNA and Y-Search websites. I have no serious problem with the FBI using my DNA info. If the FBI can use my data to catch a rapist who happens to be a distant cousin of mine, then I am happy to help.

My very minor concern is that the California detectives searched the websites by creating a user with genuine DNA but a fake profile. I hope that after the search these fake profiles are removed so that genealogical researchers aren't misled by them.
Mark Thomas
not rated yet Apr 28, 2018
Da Schneib, it is the nature of the "abandoned" DNA that troubles me. Focus on that in the article and what I wrote about that.

Shakescene21, you must be feeling pretty good about your DNA to be happy with the government and corporations doing anything they want with it for all time. Do you actually believe your DNA is perfect? It isn't. Do you care about anyone that might have less then perfect DNA? Maybe your children? How about if the government discriminates against them simply because you foolishly "abandoned" a napkin with saliva at the local McDonald's back in April 2018?

Like you, I am thrilled they caught that scum bag rapist killer, but I am not thrilled about the long-term implications of taking people's DNA simply because they went out in public and doing whatever they want with it. It sets a very bad precedence. You have to think beyond what is right in front of you to the larger implications.

Oh well, I can see I am wasting my time here.
Shakescene21
5 / 5 (1) Apr 28, 2018
@Mark Thomas: One of the long-term implications that you should consider is that it will soon become very difficult for rapists to evade the law. More than 10 million people have placed their DNA on genealogical websites, and the data base is increasing by a million a month. Within a few years nearly everyone will have a relative on these websites and rapists can be identified quickly and positively. Rape victims will be willing to step forward quickly, knowing that the rapist will be found and convicted. Since many rapists are repeat offenders, the number of rapes will decline far beyond what would be expected from deterrent effects. I would not be surprised to see rapes decline by 50-90% over the next decade.
Mark Thomas
not rated yet Apr 28, 2018
Shakescene21, I am not sure our civilization has the restraint, maturity and integrity necessary to limit the use of DNA information to legitimate scientific study, medical remediation and identification of felonious criminals. The fact that corruption is so near the surface at the moment makes me seriously doubt this. However, if we could pull this off, then yes, sign me up for a DNA analysis too because I want to help. But if not, we need to consider the chilling effects on simple gathering in public that this might cause. I really don't want to have to worry who is diving in trash for my dinner napkin and for what nefarious purpose.

granville583762
5 / 5 (3) Apr 29, 2018
Insurance companies can join the bandwagon, test your abandoned dna and charge you for it by increasing your medical insurance, slapping you with exclusion clauses for your pre-existing conditions.
granville583762
3.7 / 5 (6) Apr 29, 2018
Assumption of guilt in your abandoned dna
Why not take it further, psychoanalyse your predilection to assume your dna can eliminate you from crime to show what crimes your dna shows your capable of to get a court order to take preventive measures to keep you safe from committing these crimes, this intellectual thought process of assumption of guilt applied to crimes you may commit based on your dna is already used in correctional facilities

tblakely1357
2.3 / 5 (3) Apr 29, 2018
And don't discount the fact that many DNA 'results' are inaccurate. Nothing like being accused and discriminated against because of bad science.
humy
5 / 5 (1) Apr 29, 2018
And don't discount the fact that many DNA 'results' are inaccurate. Nothing like being accused and discriminated against because of bad science.


It couldn't credibly be inaccurate in this case. They tested his DNA twice and got a match to more than 10 of the murders. + other evidence. The most modern up-to-date DNA fingerprinting is NOT "bad science".
humy
1 / 5 (1) Apr 29, 2018
The District Attorney here has concluded you have no right to privacy in your DNA if you lose a hair or cell in public.

Mark Thomas

If you committed a crime then you forfeit any right for this so-called 'privacy'. But how would that be an invasion of your 'privacy' anyway if you committed NO crime? The DNA information wouldn't be made public at least if there was no match but rather would be just discarded. And some police or scientist in a lab temporarily looking at your DNA code are not invading your 'privacy' in any meaningful sense because your DNA code just consists of a very long boring DNA code that they would surely rapidly forget the exact sequence of even if they tried to personally memorize it, which of course they wouldn't. It wouldn't be as if they were looking at your private bodily parts like your genitals! -its just your boring DNA code; NOTHING embarrassing about it! This isn't by itself invading privacy.
baudrunner
1 / 5 (1) Apr 29, 2018
People who feel threatened that DNA profiling somehow compromises their right to privacy are people who do not want anybody to know or study their genome because it might contravene their fifth amendment rights, freedom from incrimination. I don't even know why the fifth exists, except to protect the culpable.
Da Schneib
not rated yet Apr 30, 2018
Personally I'm having trouble coming up with a nefarious purpose that can be accomplished with my DNA. If anyone can suggest with one I'd be interested to hear it.
humy
5 / 5 (1) Apr 30, 2018
Personally I'm having trouble coming up with a nefarious purpose that can be accomplished with my DNA. If anyone can suggest with one I'd be interested to hear it.

It can reveal your proneness to certain diseases and what measures you can take to minimize your chances of diseases. This would tend to be a bit different for each person. Just one small example out of many; some people have genes that require them to have less salt in their diet (those of the Australian aboriginal race being perhaps the best example) which means they have to be especially careful to consume much less salt else they would be of much higher risk of stroke and kidney failure than most other people consuming the same amount of salt.
+ Parents often want to know if they curry bad genes that could cause genetic disease in their children so to decide if they should have any.
humy
not rated yet Apr 30, 2018
I see a logical inconsistency here;
People not thinking their privacy is violated when other people see their face but think it is violated when other people see their DNA. Why aren't people up in arms about passersby glancing at their face? Answer, someone seeing your face isn't embarrassing unless you are exceptionally ugly. Same with your DNA. I don't mind someone looking at my DNA. Why should I? It isn't an invasion of my privacy. It is just a very long boring list of DNA bases.
Mark Thomas
not rated yet Apr 30, 2018
But how would that be an invasion of your 'privacy' anyway if you committed NO crime?


Humy, do I have to paint the picture for you? 1. You wipe your mouth with a napkin at a restaurant. 2. You leave the napkin at the restaurant like everybody else. 3. The government collects the "abandoned" napkin. 4. The government analyzes the napkin to map your DNA. 5. The government can do WHATEVER they want for all time with your DNA map because you "abandoned" it at the restaurant. I am arguing the 4th amendment right to privacy applies, but I seem to be in the minority here. So if you are correct, you have no rights to your DNA in the five steps I described.
humy
not rated yet Apr 30, 2018

Humy, do I have to paint the picture for you? 1. You wipe your mouth with a napkin at a restaurant. 2. You leave the napkin at the restaurant like everybody else. 3. The government collects the "abandoned" napkin. 4. The government analyzes the napkin to map your DNA. 5. The government can do WHATEVER they want for all time with your DNA map because you "abandoned" it at the restaurant. I am arguing the 4th amendment right to privacy applies, .

No it doesn't because I don't live in America.
And what could they do to my DNA that would invade my privacy even if I was American?
Even in the very unlikely event of them publicly displaying it all over the net, I would say "So what?".
And why should I care a damn if they got my DNA? All they would have to look at is a very long very boring DNA code; that's it. Nothing embarrassing or humiliating there.
Now, if they displayed my naked body over the net, THEN I say that's invading my privacy!
Mark Thomas
not rated yet Apr 30, 2018
humy, this article is about the use of DNA to apprehend an American criminal and prosecute him under American jurisprudence. Your personal situation may be very different, or you may simply believe situation is very different. If you don't understand how public disclosure of your DNA could lead to trouble, I suggest you research "misuse of DNA" on the web. You might find articles mentioning denial of employment and insurance based on racial origins, medical history and psychological profiling. The fact that you believe technology cannot be used against you suggests you are young. Technology itself is usually neutral, so it can be used for good or bad, and oftentimes both. We can use your DNA to help identify members in your family tree for tearful family reunions or exclude you from work and insurance because your family is prone to medical problems that employers and insurers do not want to deal with.
Shakescene21
not rated yet May 01, 2018
Mark Thomas, I still disagree that the 4th Amendment is relevant, because the 4th refers to protection of citizens from "unreasonable searches and seizures" by the government. Your examples refer to "unfair" uses of DNA by employers and insurance companies. It might be a good idea to restrict the use of DNA data by employers and insurers, but that is an issue for public debate and new laws at the federal and state level.

The principal government use of DNA data bases has been to catch criminals, and it has the potential to dramatically reduce rape by leading investigators to elusive criminals such as GSK, by positively confirming guilty rape suspects, and by quickly exonerating innocent suspects.
humy
1 / 5 (1) May 01, 2018
If you don't understand how public disclosure of your DNA could lead to trouble, I suggest you research "misuse of DNA" on the web. .

Mark Thomas

So, tell me, if the police collected my DNA and they found it didn't suggest I committed a crime, why would they publicly disclosure it?
They wouldn't.
That's not what the police do.

I should also point out that my DNA could just as easily help to prove me innocent of the crime. What reason would I have to complain then?

I think everyone's DNA should be on police file so that they can quickly eliminate suspects and find out who did it. That would also then put an end to this invasion of privacy crap.
434a
5 / 5 (1) May 01, 2018
If anyone can suggest with one I'd be interested to hear it.


Bearing in mind I am not one for paranoid delusions but you asked for a scenario - it may or may not be applicable to you personally.

Having your DNA means I can place you at the scene of a crime, literally I can contaminate a crime scene with your DNA.

Even, assuming you have an alibi you are reliant on a jury to exonerate you based on the evidence i.e. your DNA and expert witness testimony vs your witness testimony.

That concept could be very useful for blackmail to facilitate political, military and industrial espionage. or to remove someone from public office for example or simple increase the likelihood of a conviction.

Like any tool in the wrong hands people will get injured. It is inevitable that DNA collection will be misused at some point, as all information has been throughout history.

Society simply(!) needs to decide if the benefits will outweigh the costs.
humy
3 / 5 (2) May 01, 2018
haven't I just linked ...is also the culprit here.

Your links prove nothing of the sort.
Mark Thomas
not rated yet May 01, 2018
Shakescene21 and humy, you both concluded that privacy is unnecessary because there is no way a government could misuse knowledge of your DNA. Hilarious.

Shakescene21, yes, some of my examples refer to "unfair" uses of DNA by employers and insurance companies, but is it so hard for you to envision that employer might be the government? Millions of people work for the U.S. government. Is it also impossible to imagine that the government could give that info to private employers and big insurance companies, maybe for a price? How about the fact that if the government routines takes people's DNA information, that makes it more likely private companies will get away with it too. It goes way beyond this too. Evenutally it could create pressure on people to get their genes edited to correct those errors. After that, pressure could grow to improve their genome. Where does it all stop? Star Trek touched on this beginning over 50 years ago.
humy
1 / 5 (1) May 01, 2018
Golden State Serial Killer DNA Search Led To Wrong Man In 2017 - versus "It couldn't credibly be inaccurate in this case, your links prove nothing of the sort."

if you read your link it says DNA fingerprinting helped clear the original suspect and helped convict the one that committed the crime.
The police where sloppy and very wrong for not checking if the DNA fingerprinting was an EXACT match; but that is entirely the fault of the police, NOT the DNA fingerprinting which is still reliable.
If everyone had their DNA fingerprint on police file then, providing the police always check for an EXACT DNA fingerprint match (and I assert it should be made law that they do to prevent mistakes) then the real murderer could have been caught earlier preventing later murders and an innocent wouldn't have been accused.
At least in England, your face would be on police file so they can check you are the owner of your car. Is that also an evasion of your privacy?

humy
1 / 5 (1) May 01, 2018
Shakescene21 and humy, you both concluded that privacy is unnecessary because there is no way a government could misuse knowledge of your DNA

No I do not. Of course government could misuse knowledge of your DNA. I actually said nothing about government.
And of course government could also misuse knowledge of your name, face, address, employment, education etc.
Those potential abuses should be countered by laws restricting how they (government or police) use information, NOT by denying the police the information they may need to catch criminals and clear innocent suspects.
And your DNA isn't an invasion of your privacy; it is just a very long very boring sequence of DNA bases. There is nothing embarrassing about it.
humy
1 / 5 (1) May 01, 2018
It can lead into very serious breaking of privacy, as Golden State killer finally realized.

That wasn't "breaking of privacy" but rather "police misconduct". Privacy isn't the issue here. There is nothing embarrassing about someone seeing your DNA.
If it wasn't for DNA fingerprinting, the real killer would probably never have been found. That shows the value of DNA fingerprinting and that the science behind it is valid.
It would be good if the police had everyone's DNA on file.
carbon_unit
5 / 5 (1) May 01, 2018
Privacy issues aside, there's a heck of a story of the genealogical work that the investigators had to do to find this guy. His DNA lead to several hits on distant relatives. Investigators back tracked to find the common ancestors, his great-great-great grandparents in the early 1800's. They then had to work forward, generating family trees of successive generations until they got to individuals who were of right age to possibly have committed the crimes. (There were about a 1000 individuals just in the tree that included DeAngelo.) They then looked for individuals with links to locations where the crimes occurred. That narrowed it to two individuals, one being DeAngelo. Quite an impressive investigative effort.
https://www.washi...ory.html

Mark Thomas
not rated yet May 01, 2018
Those potential abuses should be countered by laws restricting how they (government or police) use information, NOT by denying the police the information they may need to catch criminals and clear innocent suspects.


I agree, the only problem is almost no govt. actually works this way. That kind of analysis requires considering what is best for society as a whole and working hard to actually implement that system. Propose that to most politicians and they will be RAOTFLMFAO. Once they regain their composure, they will have their donor's attorney (a lobbyist) tell them what they are going to do in the best interests of their donor. Look at guns, for example. A few simple restrictions like no guns for the mentally ill, training and registration required, no assault weapons (at least for high school students), etc., would leave most of us with our guns and still solve a lot of problems, but it is impossible to get it done in the U.S. at the moment no matter how many die.
Mark Thomas
5 / 5 (1) May 01, 2018
By the way Humy, a great many Americans are extremely sick and tired of business as usual with our Republican party. Expect regime change beginning with mid-term elections the end of this year.
humy
5 / 5 (2) May 01, 2018
By the way Humy, a great many Americans are extremely sick and tired of business as usual with our Republican party. Expect regime change beginning with mid-term elections the end of this year.

I really hope so. I am concerned with some of the things Trump has being doing. Denying the validity of climate science being just one of those things.
Mark Thomas
5 / 5 (1) May 01, 2018
I am concerned with some of the things Trump has being doing. Denying the validity of climate science being just one of those things.


I couldn't agree more.

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