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How DNA on an ancestry site identified the Golden State Killer

During a recent seminar, investigator Paul Holes detailed the methods he used to track the killer


The recent arrest of the primary suspect in the Golden State Killer case has brought great interest in the methodology and DNA database that law enforcement used to identify the serial rapist and killer.

Photo/In Public Safety

By Jennifer Bucholtz, Faculty Member, Criminal Justice and Forensic Science at American Military University

The recent arrest of the primary suspect in the Golden State Killer case has brought great interest in the methodology and DNA database that law enforcement used to identify the serial rapist and killer.

I recently attended CrimeCon 2018 and was fortunate enough to listen to a seminar hosted by Paul Holes, an investigator for the Contra Costa County District Attorney’s office, who is credited with identifying the suspect believed to be the Golden State Killer. During the seminar, Holes detailed the methods he used to link three distinct series of crimes and how the DNA from some of those cases led to the arrest.

The First Series of Burglary Crimes

From 1974-1975, there were more than 100 burglaries committed in the town of Visalia, California. Most of these took place when residents were not at home, which is not unusual. Over time, police noticed some similarities between many of the crime scenes, leading them to believe the burglaries were committed by the same person.

In several of the cases, there appeared to be evidence the perpetrator had a fascination or fetish with women’s underwear, as well as an apparent hatred towards family photos. There were other oddities, including the theft of items with little to no monetary value such as a single earring or a piggy bank. However, there were two valuable items regularly stolen during many of these burglaries: weapons and ammunition. Law enforcement eventually nicknamed the perpetrator the Visalia Ransacker.

The last known crime committed by the Visalia Ransacker involved the murder of a father protecting his teenage daughter during a burglary gone wrong. Investigators were able to link this murder to the burglaries via ballistics evidence that showed the gun used was stolen from a previous burglary victim. Despite this link, the case eventually turned cold as no more burglaries attributed to this suspect were committed.

The Emergence of the East Area Rapist

A year or so later, in 1976, police began compiling information on numerous rapes that occurred in or around Sacramento and the nearby San Francisco Bay Area – both a couple hours north of Visalia. Over the next three years, dozens of rapes were reported to law enforcement and the East Area Rapist moniker emerged. Based on behaviors and methodologies exhibited by the rapist, they were able to link many of the cases together, but had not yet associated them with the Visalia Ransacker.

The East Area Rapist was excellent at breaking into homes undetected and usually did so while the residents were sleeping at night. He was careful to wear a mask and gloves and disguise his voice to hide his identity from his victims. He often carried a flashlight, which he shone in victims’ faces to further impede their vision, said Holes during his CrimeCon presentation. All of these tactics demonstrated his level of organization, planning and self-preservation.

If the suspect encountered a sleeping couple (which seemed to be his preferred victim choice), he would tie up the male (sometimes even forcing the woman to tie up her partner), leaving him helpless, as he raped the female. Targeting multiple victims at one time is extremely risky behavior and evidence of the perpetrator’s need for power and sadism in his crimes. Rendering a male partner incapacitated while raping his wife/companion serves as a vindictive way to humiliate the victims and increase the emotional and mental suffering.

In February 1978, the suspect’s crimes escalated to murder. The perpetrator killed a young couple he encountered while they were out walking their dog in the evening. It’s possible that the East Area Rapist lost control of the victims and they tried to run away. He chased them down and shot them, perhaps out of anger and/or because he was fearful they had seen his face and could identify him to authorities. The suspect was back at it a few weeks later, committing several more rapes in the area.

At the end of the year in 1979, the East Area Rapist struck in Southern California, his third geographical location in the state. From 1979 to 1986, he killed 10 people, often attacking two people (couples) at a time, as he did in the previous series of rapes up north. The nickname attached to these murders was The Original Night Stalker (not to be confused with Richard Ramirez, a different killer who was nicknamed the Night Stalker). As before, this group of crimes was not linked to the other two.

Investigators were certain the rapes and murders of these couples living in Southern California were perpetrated by the same person because of similarities in the method of attack and behaviors exhibited during the commission of the crimes. Holes explained that the attacker would often separate the couples, forcing the females into the living room, where he would turn on the television, mute the sound and place a towel over the screen. This provided dim light in which he could view his victims as he assaulted them. After the recent arrest of the serial rapist-killer, Holes had the opportunity to examine the residence of the suspect. In the home office, he discovered a computer screen with a towel draped over it. Though certainly not a solid piece of forensic evidence, the towel-draped monitor was a possible indication of the killer reliving his crimes in later years.

In the mid-1980s, the crimes stopped, and, as of now, no further attacks have been attributed to this suspect. Holes surmised during his presentation that the perpetrator may have quit committing rapes and murders in 1986 because of incidents that occurred at the final two homicide scenes. In the second to last case, a woman and her boyfriend (Cheri Domingo and Gregory Sanchez) were beaten to death, but Sanchez, who was 6’3” and several inches taller than the offender, put up quite a fight, even after being shot in the cheek. This may have spooked the rapist-killer and led him to go on hiatus from his serial crimes for five years. It is likely he chose his next and last victim, Janelle Cruz, because she was young and unaccompanied on the night he attacked her in 1986.

How Law Enforcement Linked Three Series of Crimes Together

It took decades for law enforcement to link the three series of crimes and attribute them to the same suspect. Paul Holes was instrumental in that process. In studying the various crimes, he and fellow investigators noticed similarities between the modus operandi (MO) and on-scene behaviors of the offender:

  • His method of breaking and entering was the same in many instances.
  • He often cased his crime scenes ahead of time, hiding necessary weapons and removing window screens for easier access.
  • He stole similar types of items from victims’ residences.
  • He often used towels to blindfold his victims.
  • His level of forensic sophistication (i.e., not leaving identifiable evidence behind) was consistently high.

The Role of DNA

Despite all his planning and caution, the killer left DNA samples at many of the crime scenes without forethought as to how technology and forensics would advance over the next four decades.

It was not until recent years, when DNA samples from crimes that occurred in two of the three geographical locations were compared to each other, that investigators had proof beyond a reasonable doubt that the same person had committed the scores of crimes.

DNA was obtained from several rape and murder scenes carried out by the East Area Rapist and Original Night Stalker cases. Though police confirmed one person was responsible for the rapes and murders, they could not identify the perpetrator because his DNA was not in the national database known as CODIS (Combined DNA Index System) maintained by the FBI.

No DNA was found or collected in the burglary cases perpetrated by the Visalia Ransacker. This is likely because the suspect wore gloves and did not perpetrate any personal attacks against human victims, which would have increased the likelihood of him leaving blood or semen at the scene. Despite the lack of identifying forensic evidence at these burglary scenes, investigators are nearly positive they were committed by the same person, based on the similar MO used by the perpetrator at the various crime scenes.

How the DNA was Preserved

Year after year, the collected DNA evidence was preserved in secured evidence storage vaults by the various jurisdictions involved in the investigation of crimes in their areas.

Proper collection and storage of this biological evidence requires the DNA sample to dry completely (to avoid bacterial growth) and be stored in a temperature-controlled environment. It is common for DNA samples from unsolved cases to be frozen in order to maintain their integrity. Semen samples have been frozen for over 20 years and still been effectively analyzed and used in criminal cases.

DNA evidence is protected just like any other crime scene evidence in that the samples are stored under lock and key and the chain of custody must be adhered to if the sample is accessed by forensic analysts or investigators.

Investigators Submitted DNA to Ancestry Site

During the seminar, Paul Holes explained how he brainstormed a plan to upload the Golden State Killer’s DNA to GEDMatch, a popular ancestry site used by the general public which contains nearly one million DNA profiles. The Ventura District Attorney’s office allowed Holes’ team to use the biological samples they had kept frozen from the Golden State Killer cases. GEDMatch accepts a person’s DNA profile and compares it to all others in their database, helping them narrow down their ancestral roots and origins.

This type of database does not provide a user with anyone else’s full DNA profile, but rather finds similarities in small sections of one’s DNA to help construct a family tree. GEDMatch did not hand over any DNA profiles to authorities and their computer software operated as it does in every other user’s case; the company had no involvement in the investigation. Holes used the site just as any other user does and was legally authorized to do so because he was the “guardian” (i.e., had custody) of the killer’s DNA sample.

It was discovered the Golden State Killer’s DNA contained a rare genetic marker on the Y chromosome, which assisted investigators in identifying a couple of his ancestors. According to a genealogy expert who assisted Holes and his team, that rare marker and other points on the DNA indicated the presence of Italian ancestry in his family. Initially, the rare marker led police to an elderly man in Oregon, whose DNA also contained the same uncommon marker. A judge signed a search warrant that ordered the man to provide a DNA sample. That sample ultimately excluded him as the rapist-killer and investigators continued to analyze the other partial DNA matches found in GEDMatch.

GEDMatch returned a DNA hit with one or more of the killer’s very distant cousins with whom he shared a male relative born a couple hundred years ago. Though investigators now had a small DNA match to someone in the killer’s family, they still did not have the identity of the killer himself. The genealogy expert working with Holes’ team began a painstaking, four-month process of mapping the suspect’s cousin’s entire family tree. From the common ancestor, the expert charted several generations to the present day. He identified hundreds of relatives and created a list of possible suspects, namely males born between 1940-1960, of the right physical size, who had resided in California during the years of the crimes, said Holes.

This led Holes and fellow investigators to the suspect who was ultimately arrested for the series of crimes. The Sacramento Sheriff’s office began surveillance on the man and collected a “surreptitious DNA sample,” meaning one the suspect dropped or threw away. Examples might include a cigarette butt, coffee cup, or soda can. Forensic experts tested the sample and found a 100 percent match to the unknown DNA from the rape and murder cases collected decades earlier. This brought an end to the investigation that went unsolved for as long as 44 years.

The Takeaway from the Golden State Killer Case

The innovative way that Holes and his team used DNA to find the Golden State Killer will likely help law enforcement solve similar cold cases. In fact, Holes informed his audience at the seminar that DNA from at least one of the Zodiac Killer’s crime scenes had been uploaded to GEDMatch. He was not at liberty to divulge any results yet, but was hopeful investigators will uncover the identity of this serial killer in the near future. The Zodiac Killer has at least five murders attributed to him, but in taunting letters to police, he claimed to have killed up to 37 people in the San Francisco Bay Area in the late 1960’s.

Websites like GEDMatch are not only useful for identifying criminals, but victims as well. This was evidenced recently when an unknown murder victim from 1981, nicknamed the “Buckskin Girl,” was finally identified when investigators uploaded her DNA to a public genealogy website and found a close relative of the victim. Identifications such as this certainly bring some closure to families who have lost loved ones.

Without this new investigative technique, many family members of victims would likely live out their lives receiving no answers. Additionally, it seems logical that many more criminals will be identified and convicted as the use of genealogy databases increases. It’s a win-win for both law enforcement and victims of crimes.

About the Author: Jennifer Bucholtz is a former U.S. Army Counterintelligence Agent and a decorated veteran of the Iraq and Afghanistan wars. She holds a Bachelor of Science in criminal justice, Master of Arts in Criminal Justice and Master of Science in Forensic Sciences. Bucholtz has an extensive background in U.S. military and Department of Defense counterintelligence operations. While on active duty, she served as the Special Agent in Charge for her unit in South Korea and Assistant Special Agent in Charge at stateside duty stations. Bucholtz has also worked for the Arizona Department of Corrections and Office of the Chief Medical Examiner in New York City. She is currently an adjunct faculty member at American Military University and teaches courses in criminal justice and forensic sciences. You can contact her at For more articles featuring insight from industry experts, subscribe to In Public Safety’s bi-monthly newsletter.

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