There is nothing in the Constitution or the Bill of Rights that protects our right to be free from DNA fingerprinting. Regular fingerprinting isn't always effective, and DNA fingerprinting is much more certain of identification. If we want law enforcement agencies to do a better job, we need to make sure they have the best and most accurate tools available. DNA fingerprinting fits the bill without damaging anyone's civil liberties.
I'm sorry, but once you take it upon yourself to violate the rights of other human beings, I say you give up your own rights to the same liberties as law abiding citizens. If you go out and rape someone, or molest a child, or murder someone, and it is proven in a court of law, you should have your DNA sequenced and put on file, so that if you are ever released or escape to do it again, they'll have you square.