The last few years have seen the emergence of a
new investigative technique used by law
enforcement. When DNA is recovered from a
crime scene, law enforcement may not be able to
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against are DNA samples taken from people who
have already had contact with police. If the DNA
is from someone unknown to law enforcement,
there won’t be a match.
While there might not be a national database of
DNA to test against, home DNA testing and
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The capture of the Golden State Killer in 2018 is
an excellent case study in how the process works.
From the Washington Post:
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not a suspect. [Paul Holes, an investigator and
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spent four months building out family trees,
name by name. They pored over census records,
newspaper obituaries, gravesite locators, and
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relative...”
Starting with distant relatives in the 1800s,
investigators were able to winnow down the
family trees, removing people from the wrong
time frame and location. Eventually, they settled
on Joseph James DeAngelo, and used discarded
DNA to link him directly to the case. In 2018, he
was arrested for heinous, violent acts committed
about 40 years prior.
Investigators were able to connect the DNA to
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