By Rosemary Bailey
This article was published in the December 2021 edition of Soul Search, the Journal of The Sole Society
The DNA data collected by GEDmatch, a genealogical DNA testing organisation, resulted in a conviction and sentencing of multiple murder Joseph DeAngelo this summer.
The murderer, nick-named the Golden State killer, had killed at least 13, raped 50 women and committed 150 burglaries across California. DNA from the crime scene was compared with that in GEDmatch distant relatives were identified. This enabled investigators to build about 25 different family trees. The tree that eventually linked to DeAngelo to the crimes alone contained approximately 1,000 people including his 4xgreat grandfather. The investigators then used other clues like age, sex, and place of residence to rule out people on the trees, eliminating them one by one until only DeAngelo remained.
In another case a body found in 1990 in south west Missouri was identified using the same technique.
This does of course raise ethical questions of use of people’s DNA in this way, for which may not have not given consent. Your DNA is now safe, as today users of Gedmatch have to ‘opt in’ to allow their DNA to be used by the police.