A case that left detectives stumped for decades is now being called a major victory after California law enforcement used DNA evidence to identify and arrest who they say is the “Golden State Killer.”

But now, the ethics surrounding their investigative methods are being questioned. 

How California law enforcement finally made an arrest in the “Golden State Killer” case is like something out of a crime drama. 

They had a DNA sample but hit a brick wall when they could not find a match in the national database.

They then submitted the DNA to GEDmatch which does DNA and genealogical analysis. 

That is where the first potential legal issue comes in, as investigators were untruthful in claiming that they were authorized to submit the DNA for analysis. 

“It wasn’t the acquisition of that crime scene DNA. What it was was the acquisition of the familial DNA through the genealogy website. Being untruthful about their ownership or their control or their use of the DNA, that’s the part of it that could be a fourth amendment issue,” said attorney Diana Crutchfield. 

Using the genealogical information they found, they were able to narrow down a list of suspects to 72-year-old Joseph DeAngelo. 

Investigators then compared their DNA sample to DeAngelo’s discarded DNA. 

Discarded DNA typically comes from something the suspect has thrown away, like a cigarette butt or a paper cup. 

It does not take much to get a large enough DNA sample. 

“If you shed a piece of skin that falls at a crime scene, there are individual skin cells that we can use to isolate DNA from. We really need a very small sample to get enough DNA to use for genealogy or for crime scene identification,” said Deanna Schmitt, Assistant Professor of Biology at West Liberty University. 

The discarded DNA could potentially be a legal issue depending on what exactly the DNA was extracted from. 

No matter what happens from this point forward, it is no doubt that the use of genealogical research and DNA has made an impact on how law enforcement will investigate crimes from here on out.