According to the DA, they could not get a good DNA sample in Thailand, mostly because Karr didn't know he was under surveillance.

And DNA samples can be taken either voluntarily, or thru a court order.

Because the facilities for processing a fresh )"boccal") DNA sample were in the States, and Mr Karr (I think) wasn't cooperative, away he went to the USA.

At least he'll face the other charges in CA that he ran away from a few years ago.