August 5


Did You Know That Even If You’re Not A Suspect, Your DNA Could Be Used As Evidence In A Crime?

This new technology is solving decades-old cold cases

DNA has been used to identify suspects in hundreds of thousands of criminal cases since the 1990s. The national criminal database, CODIS, currently contains the genetic data of over 13 million people, along with fingerprints and other biometric data collected by law enforcement.

Although the FBI is the only federal agency authorized to maintain a national DNA database, many states, and even local law enforcement agencies, have also begun to collect DNA and maintain their own databases.

But did you know that even if you’ve never had a DNA sample collected by a law enforcement or government agency, today your DNA might be involved in a criminal investigation?

The use of familial DNA searches, the process of examining and comparing the DNA of people who might be related to a suspect, is being used by law enforcement to solve a significant number of criminal cases.

Some of these are cold cases that have been open for decades.

The National District Attorney’s Association describes familial DNA search process:

“Familial searching is a technique whereby a crime scene profile is deliberately run through the offender databank in the hopes of getting a list of profiles that are genetically similar to the DNA evidence and using this information as an investigative lead to interview family members of the near matches.” provides more details about the process:

“When a DNA profile is obtained from a crime scene and that profile is passed through the FBI’s electronic program, the Combined DNA Index System (CODIS), a perfect hit will be obtained if all 26 alleles match a DNA profile in the database, indicating that the DNA sample is from the same person. But if a partial match occurs on at least 15 or more alleles then this could indicate that a close relative left the sample at the crime scene. A relative whose past conviction or arrest required him to provide his DNA can now send another family member to prison.”

(An “allele” as referenced by is a variation in a gene that is found in a specific spot on a chromosome, which, as I understand it, is a molecule containing all or part of a person’s DNA.)

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By expanding this process to include DNA data from other public sources and private companies, investigators now have the ability to go beyond the data contained in criminal databases in order to help identify suspects.

Perhaps the most notable example solved with this new technique is the California case of the Golden State Killer. A double murder occurred in 1980, and the suspect left DNA evidence at the crime scene. But investigators couldn’t match the DNA to any record in a criminal database, and without additional information, there weren’t any other leads.

Millions of people have submitted DNA samples to companies in the genetics industry to discover their ancestry or to see whether they have genetic markers that might indicate a higher potential for some diseases.

In addition to the information given to the customers, the genetic databases are valuable to medical researchers. The data can potentially be used to find the genetic causes of various diseases and medical disorders, which could lead to cures.

The resulting databases of genetic information contain millions of records from people who are not contained in criminal databases. This data is now being used by law enforcement, even though the people who submitted samples may not have been aware that law enforcement would have access to these records.

In April of 2018, investigators uploaded the DNA evidence related to the Golden State Killer to an open-source, public genealogy website named GEDmatch. With an account, anyone can see genetic data without a court order, usually when looking for unknown or distant relatives.

After setting up a fake profile account on the service, investigators used the same type of familial search and were able to match the unknown suspect’s DNA with possible relatives. By following the known family tree, investigators used more traditional investigative techniques, such as eliminating people by age, death, known locations, and gender to narrow down the list of potential suspects.

The data provided by this new field of familial genetics forensics identified the suspect, Joseph James D’Angelo. An ex-police officer, D’Angelo is a possible suspect in 13 murders, 50 rapes, and over 100 burglaries committed between 1974 and 1986. Even though D’Angelo was later cleared of the double murder charge (also after further DNA analysis), he still faces charges in the other crimes.

In the past year, over 50 other cold cases have been solved using this method.

Just recently, a Washington state court ruled that the use of familial genetics evidence that identified a suspect from another cold murder case could be admissible in his trial. After the initial DNA analysis from the crime scene was uploaded to GEDmatch, the database produced a match with a pair of second cousins to the DNA sample. A genetics forensics expert then reviewed the family tree and looked through newspaper articles, obituaries, census records, and even social media posts to follow the family tree leads. Her analysis targeted a male suspect, William Earl Talbott II.

Based on the DNA analysis, investigators placed the suspect under surveillance and collected a cup that the suspect had thrown away. His DNA was taken from the container and used for a direct comparison with DNA from the 1987 murder. The DNA matched.

However, with no other corroborating evidence, it will be up to the prosecutors in the case to determine whether the DNA analysis alone is enough to obtain a conviction.

The success of familial genetics forensics will only increase with the data volume as the number of customers grows. Private genetics companies have databases that contain millions of genetic profiles. GEDmatch (which is public) includes over 1.2 million records. Family Tree DNA has approximately another million profiles. But the more prominent players in the industry have much larger databases (23andMe – 10 million and – 15 million records). The terms of service for each organization are different related to law enforcement access, which complicates the situation even more.

Should You Think Differently About DNA?

You could make an argument that DNA is different from other types of biometric data. DNA is what makes you uniquely you, but unlike other biometrics such as fingerprints, iris scans, or face prints, parts of your DNA are shared with people related to you.

Consider the possibility of an innocent person whose DNA resembles the DNA found at a crime scene being questioned about other family members.

  • How many people would be comfortable in this scenario?
  • Would everyone agree to his or her DNA records and other related information being reviewed by law enforcement during a familial genetics investigation?
  • Do individuals have a right to be concerned about the privacy of their biometric data?
  • What about the security of digitized biometric data, and what would the possible consequences be if that data were stolen?

What Do You Mean There Are No Laws Regarding DNA?

There are currently no federal or state laws addressing the ownership of an individual’s DNA. Customers need to review the laboratory’s or company’s terms of service and privacy policies for this answer and many other issues.

The prevailing practice is that once a sample is submitted for analysis, the individual owns the sample until it is processed. Once processing is complete, the lab or company where it was sent owns the data.

Once ownership has transferred, the person who submitted the sample has no control over what the data is used for, how it is shared, or to whom it is sold.

There are no regulations about how your DNA might be used, and for what purpose.

Possible consequences might include:

  • Being turned down for insurance coverage due to something in your DNA.
  • In the United States, the Genetic Information Nondiscrimination Act (2008) prohibits unfair treatment related to medical insurance but does not address how life, disability, or long-term insurance providers may act.
  • How might DNA markers indicating intelligence be used?
  • Could your DNA become part of a pre-hiring due-diligence review?
  • Some researchers want to link DNA profiles to income and other data to look for correlations. Even though this might produce interesting results, could this type of data also result in discrimination?
  • Could the ethnicity and/or race markers from full DNA profiles be used in a discriminatory fashion?
  • What would the impact be in situations where the suspect was adopted?

Should law enforcement have unrestricted access to your DNA?

Some legal experts think that access to DNA profiles by law enforcement is a violation of the Fourth Amendment, and should require either a search warrant or a court order to access.

In other cases, courts have ruled that if people voluntarily provide information (or a biometric sample) to a third party, they have waived their right to privacy.

Some of the commercial genetics companies restrict access by law enforcement in their terms of service to cases involving only murder or violent crimes, but there is no consistency from service to service.

The DNA usually collected from people arrested by law enforcement doesn’t typically include a full profile like the ones produced by the genetics firms, and doesn’t include things like physical characteristics or medical/genetic disorders.

There is a growing debate about providing these more detailed profiles to law enforcement. Andrea Roth, Director of the University of California Berkeley Center for Law and Technology, said: “All the Supreme Court decisions about why existing offender databases don’t violate Fourth Amendment rights are all premised on the presumption that nothing personal can be gleaned from this junk DNA. Now that’s all up in the air. I think the bottom line is now everybody is about to be under genetic surveillance one way or another, unless we regulate the government’s ability to conduct genealogy searches.”

The counter-argument to this view is that familial genetics forensics has identified extremely violent criminal suspects who avoided detection for years (if not decades).

But what about the privacy of a criminal suspect’s relatives, and the fact that they could be considered as potential suspects in a crime they had no part in? In using DNA and genealogy to build family trees, even people who have never submitted a DNA sample might now be included in the suspect pool.

As you can imagine, there are lots of arguments about this process, and no legal precedents to give definitive answers.


The legal and privacy issues surrounding this new practice of familial genetics forensics raise many questions. Inadequate law, lack of regulations, inconsistent terms of service, the ability of customers to “opt out,” and practices involving the use of DNA by law enforcement are all factors that need additional discussion.

I’m sure a high percentage of people who’ve sent their DNA to one of the genetics companies were never explicitly told that their profile might be involved in a criminal investigation. Perhaps more transparency from the firms to make this clear would help, but they don’t have much incentive, and there are no regulations that require this type of notice.

People might also have second thoughts about submitting a DNA sample to one of these companies if they realized all the ways that their DNA data might be used or sold.

It’s becoming even more complicated when you consider how often private companies and government agencies are collecting biometric data at all levels.

Do we need laws or regulations about privacy for this type of data?

Or should there be no restrictions, since the owners of the commercial services now own the data related to the customer’s DNA, and can use it however they please?

On the other hand, after over 20 years in law enforcement, I recognize the need to be able to identify and arrest criminals, especially in violent cases, because without this technology they might escape responsibility for their crimes.

An article entitled “A Great Time to Be a Cold Case Detective — If We Can Use The Tools,” by Cloyd Steiger, Chief Criminal Investigator of the Washington State Attorney General Homicide Investigation Tracking System, expresses it well:

“I suggest lawmakers and lab administrators who are reluctant to use these techniques sit in a room and look into the dead eyes of a mother who lost a child to murder years ago. Explain to her that using this technology is a bad idea.”

There’s no argument about the value of this new source of evidence gathering. But we all need to work together to make sure that the legal and privacy issues are addressed, and that the chances for unintended consequences, misunderstandings, and abuse are resolved.

What do you think?

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