What is the best way to get an accurate DNA swap secretly?

Question

I know this swab will not stand up in the court system but at least it could give us a heads up if we ever do have to take this situation to the courts and a DNA is ordered by the judge.

Answer 1

No.  Not only will it not stand up in court, it's illegal for you do so without the person's consent, no matter what the reason.

Answer 2

Wait until the person in question is done drinking a soda from a can and puts it in the trash or smoking or something to that matter and once it leaves their hand and hits the ground or trash....its considered public property and it is free game.

Answer 3

a hair off a hair brush

Answer 4

You can get DNA from hair, but only if the skin on the root is still attached.  If you're talking about a cheek swab it would be difficult to get that unless you were able to sneak in and get it while the person was sleeping.  I actually don't think it would be illegal to get someone's DNA unless they've enacted some new laws recently for exactly this reason.