Those in middle age are likely to remember a very popular cable TV documentary series called The New Detectives. The show focused on advances in forensic technology that allowed modern-day investigators to solve crimes and track down killers that detectives of the past could never have dreamed of getting on top of.
The show focused heavily on the then-new practice of collecting biological DNA evidence at crime scenes. Advances in DNA analysis did for 20th century detective work what the discovery of the uniqueness of fingerprints did for detectives in the 19th century.
There’s another advancement in DNA taking the forensic world by storm: genetic genealogy. The practice is being increasingly used to solve cases that would have been put on the cold shelf just a few years ago.
The latest victory for the technique is the arrest of Dana Shepherd, 52, of Missouri, for the 1993 rape and murder of 19-year-old Indianapolis woman Carmen Van Huss. Her father found her lifeless body in her apartment when she did not show up for work. Kendale Adams, deputy police chief in Indianapolis, said the Van Huss family has spent 31 years grieving and he hopes the arrest gives them “some measure of peace.”
What is Genetic Geneaology?
It all starts with DNA, the tiny molecule that contains the instructions for building an organism. Every known life form on Earth is built from DNA. What makes it special for solving crimes is the same thing that makes fingerprints so useful: each person’s DNA is unique. The only people who have the exact same DNA are identical twins.
But for DNA to be useful to crime investigators, they have to have a name to put with the genetic profile that comes back from the lab. When a suspect is a known criminal, his DNA profile is often found inside databases shared by police departments nationally and internationally. But that is not always the case. Some crimes are “first time,” and some criminals manage to evade capture, so their DNA may be extracted from a crime scene, but investigators have no idea who it may belong to.
Enter genetic genealogy. Since DNA testing has become more routine and affordable, commercial services such as the well-known site Ancestry.com have begun offering to bank DNA from customers in order to compare it with other submitted samples. This can allow people to construct more detailed and accurate family trees much quicker than researching obituaries on microfilm or visiting cemeteries to get data from gravestones.
It’s easy to see how this can catch a killer. Forensic investigators work with genealogical DNA banks to triangulate suspects by comparing DNA taken from crime scenes to samples voluntarily submitted by others. Once they detect a family relationship, detectives work to narrow down who it may be.
The technique was most famously used to capture Joseph DeAngelo, the so-called Golden State Killer, in 2020. DeAngelo was convicted after confessing to 13 murders and 50 rapes during the 1970s and 1980s.
