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House Votes To Expand National DNA Arrest Database
suraj.sun writes with this excerpt from CNET: "Millions of Americans arrested for but not convicted of crimes will likely have their DNA forcibly extracted and added to a national database, according to a bill approved by the US House of Representatives on Tuesday. By a 357 to 32 vote, the House approved legislation that will pay state governments to require DNA samples, which could mean drawing blood with a needle, from adults 'arrested for' certain serious crimes. Not one Democrat voted against the database measure, which would hand out about $75 million to states that agree to make such testing mandatory. ... But civil libertarians say DNA samples should be required only from people who have been convicted of crimes, and argue that if there is probable cause to believe that someone is involved in a crime, a judge can sign a warrant allowing a blood sample or cheek swab to be forcibly extracted."
DNA evidence is increasingly used to convict even where the rest of the evidence is tenuous at best. Jurors, who mostly do not understand the science behind DNA, will accept that DNA evidence must mean the accused is guilty. The problem is that there are many ways in which an innocent person can be convicted on the basis of DNA "evidence". First of all we have cross-contamination of a crime scene. Next up. cross contamination (or downright incompetence) in the lab. Next we have increasing evidence that the current science behind DNA forensic analysis is not fool-proof: the tests only look for a finite number of specific markers on the DNA sample, and it appears that there is a non-zero chance that you share a genetic fingerprint with some other person. In fact the methods used are so weak that you may even share a marker with someone who is a different race than you. As the available DNA database grows the chances of such a false positive also increases.