This Veritasium video gives a great overview of how genetic information can be used to solve criminal cases nowadays. The idea is that the criminal’s DNA doesn’t have to be on anyone’s database—genetic information from the relatives (e.g. from genetic testing companies) can be partially matched to the DNA found at the crime scene. This allows to narrow down possible suspects to very few individuals.
I cannot imagine how important this is to the victims' families, but the increasing availability of genetic information scares me a lot too. Not only the fact that it could be abused by governments or insurance companies (as mentioned in the video), but also the fact that catastrophic data breaches do happen. Even if you’ve never used the services of genetic testing companies, a fuzzy signature of your DNA is already stored on someone’s servers. Your DNA is not your password or your credit card—if it gets stolen, you can’t just change it. Today, the damage would probably be limited. But I’m worried how tomorrow’s technology will change the calculus.