This arstechinica article is interesting, not for the macabre description of what the poor people had to endure before their eventual deaths. Rather that today, generations later, scientists are able to identify the remains of the bodies from DNA supplied by relatives alive today.

In this instance, analysis of the DNA is awesome. My second thought was hang on, what about crime detection. We have the ability to link your DNA to some distant relative.

DNA is at a crime scene could be run through a database to try to find a family match. Once the family has been identified you have massively reduced your search space of who was present.

Who is related to you is open data via birth certificates. Combine this with an electoral register to find a family that are within a certain distance and you are narrowing down the window. People don't usually travel far to commit a crime.

I had not really realised that a DNA database of people could be used for broad searches until I read that articles. I am not a criminal but I find it slightly scary and it is not something that has been discussed publicly. Maybe I have not been paying attention as this topic came up in the comments section.

I should like the idea of crime reduction but I can't help think the potential for unforeseen consequences is high. I guess I want to live in a society where people are free to do crime with the chance to get away with it but choose not to, naive right?

Having said that this is most useful in premeditated crime. Surveillance culture and phone location data pretty much capture similar information and are probably a cheaper and more effective approach in other cases. Assuming your country's legal system allows it.

I assume for premeditated crime people leave their phones on but at home and have a hobby that is not trackable like reading rather than online gaming. The phone not moving is then not an unusual behaviour. Also live somewhere where you can sneak out of you home undetected. Use cash.

So the question I was left with what sampling size of the population of a country needs to be in a DNA database for it to be reasonably effective at these broad searches?