Genetic data is all the rage these days. You can use it for finding long-lost ancestors, identifying your risk for diseases, cracking open a decades-long serial killer cold case… wait, what? Last Thursday, Sacramento County investigators let us know how they finally were able to catch the notorious Golden State Killer—by uploading his genetic data to a website. Using GEDmatch, an open-source genealogical data tool, police were able to use crime scene data from years ago to greatly narrow down their suspect pool. So that’s cool and all, and great job to investigators for finding a crafty way to nab this guy. But there’s some valid data privacy concerns this brings up, especially considering authorities didn’t reach out to GEDmatch in order to use its tools for this purpose.