DNA evidence can be used to convict criminals, and it has successfully been used to exonerate individuals, some of whom were wrongly imprisoned for more than two decades. Often, when a person who has been convicted of a crime tries to get DNA evidence admitted as evidence, the courts are reluctant, despite the fact that such evidence could exonerate an innocent person.
Often, the person who is wrongly convicted of a serious crime such as murder or rape has a criminal record for petty crimes, which means a record already exists. Civil libertarians have argued that many of these individuals were arrested and convicted more as a matter of expediency than of true suspicion.
The Innocence Project, created in 1992 by Peter Neufeld and Barry Scheck at the Benjamin Cardozo School of Law in New York, works to exonerate people by use of postconviction DNA, in which DNA from the crime scene is tested against the accused’s DNA. Often, physical evidence from a crime is kept for many years. If the evidence includes samples of blood, hair, skin, or other evidence that can include DNA, and if that evidence has not been contaminated or corrupted, it can often be used to prove a person’s innocence. Between 1992 and 2005, the Innocence Project helped exonerate 173 prisoners.