DNA testing solves a cold case.
Companies like AncestryDNA and 23AndMe, which are direct-to-consumer, "work very hard to protect their customers' privacy," and generally do not allow their DNA samples to be searched by authorities, Moore said.
However, those companies do allow users to download their raw data. And third-party genealogy databases like GEDMatch permit people to upload their DNA information, making the samples widely available for searches -- and that's how genetic genealogists have been cracking these cold cases.
Moore said the genealogy "community has a lot of trust in GEDmatch;" however, GEDmatch "couldn't control how someone might use their database because they allow uploads. That's how they function. They're not the ones testing the DNA -- they're accepting raw data files from the commercial companies that test the data."
"If you're someone who highly values your privacy then [third-party sites] may not be something you want to participate in because you can't be guaranteed the same level of protection that you would from a huge corporation [like AncestryDNA and 23AndMe]," Moore said.
To District Attorney Greg Totten of Ventura County, where the unknown "Golden State Killer"'s DNA was first retrieved from the 1980 double murder, "the bottom line here is we have brought a serial killer, serial rapist and a dangerous predator to justice as a result of that."
"People use this database to search their family tree, to search for relatives. It is a public database," Totten told ABC News in April. "For the crime victims, the horror of the crime, the sense of loss, just the harm that is done by the crime, it can be lifelong. So perhaps the most gratifying aspect of this case was we could finally begin the healing process and the closure process for the countless victims that this individual had preyed upon."