DNA identification has moved from an experimental technique to an established crime-solving tool for police and prosecutors in the United States, as well as other nations. Now, law enforcement agencies are creating DNA databases of criminal offenders that can be used to link criminals or suspects to unsolved crimes. All 50 states have laws requiring DNA profiling of some offenders, and some law enforcement officials want to compile DNA profiles of arrestees as well. Defense lawyers are also using DNA analysis to challenge old convictions; more than 60 prisoners – some on death row – have been exonerated by DNA testing. But civil liberties and privacy advocates say expanding government DNA databases will lead to misuse of sensitive personal information that can be gleaned from DNA analysis.