If you are a criminal, it might be wise to send them someone else's DNA in your own name. From someone who is not in the register and never gets there, maybe dies soon. When they start to eliminate suspects based on DNA you get dropped.
What you actually want to do is send your own DNA in someone else's name - preferably someone who is demographically similar to you, but who has essentially no connection to you (better still, someone who is dead)
If none of your relatives use the service then this might work.
Faking your own dna has little effect on this process of triangulation and can easily be identified as you won’t share expected traits with relatives.
Good luck...
The key was that the DNA of his relatives led them to him. Once you are in that position, you are already done.