How could that be linked to you? Suppose my DNA is on the person I brushed on the street today. How would a government agent be able to prove that whatever DNA they extract from his coat sleeve is mine? In order to do so, they would have to have a sample of my own DNA. It is unlikely a judge would sign a warrant for my DNA, given that I am not even suspected of any crime.

You argue that a judge could issue a warrant on an innocent person. However, warrants are only issued if there is enough plausibility that a person could be guilty of a crime. At the point the warrant is issued, the government can now force you to give your DNA. But that could happen right now.

Ultimately, in this case, the FBI barely exercised any of their authority. They didn't do any backroom dealings or use 'secret' laws. They just signed up to a genealogy website where people freely share their DNA information with the DNA sample voluntarily given to them by a rapist and murderer. The rapist has no right to any kind of privacy after giving his DNA away. Moreover, no one has any right to prevent a person who shares their genetic information from not disclosing it.

> How would a government agent be able to prove that whatever DNA they extract from his coat sleeve is mine?

Because your cousin was arrested in 1999 for burglary and held for 30 hours until they realized they had the wrong guy.

You can easily get somebody's DNA without their explicit consent btw. Just go through their trash.

> Suppose my DNA is on the person I brushed on the street today. How would a government agent be able to prove that whatever DNA they extract from his coat sleeve is mine? In order to do so, they would have to have a sample of my own DNA.

That is exactly what the article is about: using large genetic databases to find DNA they have never collected in connection to an investigation.

They never collected the rapist's family's DNA. All the FBI has ever had access to was the rapists DNA (from his semen). They matched it using a service that his relative opted into. The rapist has no right to control relative's DNA.

And I believe it wasn't even a close relative. DNA matching can identify relatives many generations separated from someone, by finding stretches of DNA with the same set of specific mutations (haplotype) that have not yet been broken by recombination.

What this means is that getting just a small fraction of the population into this database will enable it to provide leads for any DNA sample.

> The rapist has no right to any kind of privacy after giving his DNA away.

Umm...

The person who shared their DNA was neither a rapist or murderer but was simply related to one.

Right... but how did they have anything to match it too? They have the rapists DNA because he left his semen in the women he raped.