The Golden State Killer (GSK), as he was dubbed by the media, went on a prolific crime spree in ten northern California counties between 1974 and 1986, murdering as many as 13 people, committing 45 or more rapes, and burglarizing more than 120 homes. He left DNA evidence at some, if not all, of his crime scenes.


GSK’s crime spree occurred during an era when DNA was an unknown science. “DNA testing,” as it became known, was discovered as a crime solving tool in Britain in 1985. It was first used in the United States in 1987 to convict a Florida rapist. It has since become an invaluable law enforcement tool, especially in cold cases, to connect unknown offenders to known crimes, and it has become the leading tool used by innocence projects across the country trying to free individuals wrongfully convicted of crimes.


99.9 percent of all humans share genetically similar DNA. It is that 0.1 percent difference that law enforcement utilizes to match offenders to crimes. The flaw in this investigative technique is that an DNA found at a crime scene must be matched to either a known suspects DNA or to a profile stored in a database that investigators can access.  The primary database maintained and used by law enforcement is the Combined DNA Index System(CODIS), which, in combination with The National DNA Index System, can compare suspect DNA to known DNA profiles of individuals arrested or convicted of certain offenses, as well as DNA from human remains, missing persons and relatives of missing persons.


No Sample Stored for GSK


The problem in the Golden State Killer case was that GSK had never been arrested for an offense requiring the taking of a DNA sample for storing in a law enforcement database (such as CODIS), nor had he ever submitted or donated his DNA to any genealogy database that could be accessed by law enforcement.


The DNA landscape began to dramatically change at the turn of the century. Just as law enforcement now closely monitor social media for crime-solving tips or evidence, the police some unknown number of years ago began accessing genealogy databases seeking “matches” between offenders and unsolved crimes.


Law enforcement does not seek, nor do they really need under the current state of Fourth Amendment law, permission from these genealogy databases to search them. Most, if not all, of these databases would demand that law enforcement secure a court order before they would give access to their stored material to investigators involved in a crime-solving mission. Because of that position, law enforcement just assumes a right to access for the “public good.”


Familial DNA Searching


Then 2002  the United Kingdom pioneered a new technology that allowed law enforcement to identify terrorists or violent criminals whose DNA profile has never been entered into a law enforcement database through a technique known as “familial searching.”


With this technique, law enforcement compiles a crime scene profile and then runs it through law enforcement DNA databases in hopes of identifying the suspect or a family member whose DNA has been collected and stored. The first familial DNA search in the United States that led by a conviction was conducted by the Denver Police Department in 2009.


The following year a familial search led to the capture of another notorious California serial killer—the “Grim Sleeper” who murdered at least eight people between 1985 and 1988. In that case, the Grim Sleeper’s father’s DNA profile had been entered into a law enforcement database allowing the police to make a connection between father and son.


Genealogy Databases Prove Fertile Ground


Reaping the benefit of these successes, law enforcement expanded its search field into genealogy databases, where individuals submit or donate their DNA to genealogy projects, assuming it will be used for genealogical purposes only. These individuals are not advised or warned that their DNA profile can be accessed to locate a family member who may have committed a crime. In other words, these people unwittingly become “genetic snitches.”


Only twelve states allow familial searches, including Texas. Under the direction of the State Attorney General Jerry Brown, California became the first to implement written policies governing familial searching. California, Texas, Colorado and Virginia now routinely use familial DNA software along with standard investigatory and evidence gathering techniques.


However, before these states conduct a familial DNA search, “the chief law enforcement officer and/or the district attorney must provide written certification of the request to the state investigations bureau that documents the reason for the search. There are certain requirements mandated by each state for a familial DNA search to be performed (i.e. public safety concerns, all leads are exhausted, traditional CODIS search produced no results, the evidence exhibits a full DNA profile, etc.) …”


Familial DNA Searches in Texas


The first Texas familial DNA search was performed in 2010. Texas now has a written policy that requires a joint request from both the investigating agency and the District Attorney that “all investigative leads have been exhausted.” These searches can only be performed in murder, sexual assault or other cases involving “significant public concerns.” The joint request is then sent to the State CODIS Administrator who will forward it to a committee of four CODIS analysts who can seek legal advice or investigative assistance from the Texas Rangers. The committee then sends its recommendation to the Director of the Texas Department of Public Safety through a designated chain of command whereupon the Director will decide whether the search is actually performed.


These safeguards are necessary because familial DNA searches have an 83 percent failure rate, and are outright banned in the State of Maryland and are not permitted at the federal level. Take the Golden State Killer case, for example. Last year an innocent Oregon man unknowingly got caught up in the GSK investigation after California investigators began scouring genetic websites hoping to find a familial match with GSK.


According to the Chicago Tribune, California investigators in March 2017 convinced an Oregon City police officer to secure a warrant from a judge compelling a 73-year-old nursing home resident to give a sample of his DNA because California authorities were convinced, based on their search of a genealogy website, that the resident was GSK. The nursing home resident was, and still is, in bad health. Unfortunately, however, he shared a “rare genetic marker” with GSK. His family, reported the Tribune, was not made aware that their love one was a Golden State Killer suspect, much less that the authorities had taken his DNA sample while he was lying seriously ill in a bed at the nursing home.


Ultimately, California investigators became convinced the Oregon nursing home resident was not GSK and that he had been misidentified.




Undeterred, California authorities then moved on to perform a search of another genealogy website called GEDMatch. The co-founder of the website, Curtis Rogers, told the media that he and others had no idea California authorities were searching the site looking for familial DNA evidence among its 189,000 profiles stored on their site that would connect one of those profiles to GSK.


Familial Searched and Privacy Rights


Critics of this law enforcement DNA familial searching technique have expressed deep reservations about such search practices, saying they could—and, in fact, some say they do—infringe on privacy rights.


Steve Mercer, the chief attorney for the forensic division of the Maryland Office of the Public Defender, told the Tribune: “People who submit DNA for ancestors testing are unwittingly becoming genetic informants on their innocent family.”


DNA expert and professor at New York University School of Law, Erin Murphy, sees the issue differently. “It seems crazy to say a police officer investigating a very serious crime can’t do something your cousin can do,” she told the Tribune.


The search of GEDMatch led officers to 72-year-old Joseph James DeAngelo. The former law enforcement officer was arrested on April 27 in a Sacramento suburb called Citrus Heights. Paul Holes, a recently retired investigator with California’s Contra Costa County District Attorney’s Office, conducted the GEDMatch search. He is convinced of two things: first, he did nothing wrong in the way he identified and located the Golden State Killer, and, second, he is convinced this time they got the right man with the arrest of DeAngelo.


We are not as certain.  We will let a jury make that determination.