Investigative Genetic Genealogy
In the summer of 1976, Phyllis Henneman was awoken by a man in a ski mask in her Sacramento home. She was gagged, raped, and burglarized but survived. She described her life after that day as “irrevocably changed”, her “sense of safety was shattered”. Over the next decade, the burglar continued to terrorize Californians before escalating to “attack couples, tie up both victims, rape the female, and then murder them”. Ultimately, the killer committed at least 13 murders, 50 rapes, and 120 burglaries, becoming one of the most prolific serial killers in US history and given the monikers the Visalia Ransacker, East Area Rapist, Original Nightstalker, Diamond Knot Killer and, most infamously, the Golden State Killer.
…show more content…
Detectives identified 20 relatives of the killer and traced their family tree to find a man fitting the Golden State Killer’s description. Joseph James Deangelo – a now 74-year-old former police officer from Exeter, California – was matched, arrested, and pleaded guilty to 13 counts of first-degree murder. Since identifying the Golden State Killer, investigative genetic genealogy – powered by progress in genetic technology, availability of genealogy resources, and trained teams of professionals – has drastically, and controversially, changed the landscape of detective …show more content…
Today, the FBI has DNA records of more than 5 million convicted offenders in the database CODIS, or Combined DNA Index System. However, DNA fingerprinting has limitations: it is limited to directly connecting crimes to felons already in CODIS, has high risk of contamination, does not look at familial records, and only analyzes short pieces of DNA.
With the advent of more affordable and high resolution genetic technologies after The Human Genome Project, over 35 million people have submitted their DNA to the largest direct-to-consumer genetic companies. Two companies, FamilyTreeDNA and GEDmatch, also allow law enforcement access to their databases. Thus, beginning investigative genetic genealogy, a new method of forensic investigation not only with higher resolution DNA information than DNA fingerprinting but also the capability of finding a suspect from distant relatives.
Applying Genetic Genealogy to