DNA gets criminal status

Today, DNA evidence is used as routinely as fingerprints to help prosecute criminals as well as to help free those wrongly convicted. Usually, in these cases, the accused has been identified. But New York City Mayor Michael Bloomberg this month announced that the city would henceforth begin indicting DNA itself when there is no known suspect.Under the new program, called the John Doe Indictment Project, authorities will link unsolved sex crimes with the attackers' genetic code and file charges against them even before a suspect has been identified or arrested. This will allow officials to satisfy the state's statute of limitations on such crimes, which does not allow prosecutions after 10 years. Thus, a rapist from whom semen was gathered and stored but who was never identified may be tried at any time should officials obtain matching DNA. While the strategy has been used sparingly in New York and elsewhere in the past, Bloomberg declared that the policy will now become standard practice in the Big Apple.At first, the project, which is funded by a $350,000 grant from the US Department of Justice, will look at DNA evidence collected in more than 600 unsolved sex assaults in New York City that occurred 9 years ago. Prosecutors and scientists are starting with the 1994 cases because they are fast approaching the 10-year deadline.But some experts are concerned that circumventing the statute of limitations will make it harder for suspects to defend themselves since evidence may have been lost and witnesses may have died or their memories faded. "Statutes of limitation exist for sound reasons of justice and fairness as well as practicality," said Ben Rich, who teaches bioethics at the University of California Davis School of Medicine. "Someone who is put in the position of defending himself against criminal charges decades after he allegedly perpetrated the offence is placed at an incredible disadvantage."And while it's true that DNA is much more reliable than an eye witness, especially as time passes, DNA evidence in and of itself does not necessarily mean a suspect is guilty of a crime, noted Clifton Bishop, director of the Forensic Identification Program at West Virginia University. "The limitation of DNA analysis is that it does not provide temporal linkage of the evidence with the commission of the crime," said Bishop. "When the temporal linkage is in doubt, then the existing statue of limitations would seem appropriate."There is also worry that the technology used to collect, store, and test older samples of DNA may not be reliable enough to indict suspects. But, according to Bishop, as long as the starting material is of sufficient quality, quantity, and purity, existing techniques should be adequate. "In DNA fingerprinting, the primary concern is the purity and quality of the DNA recovered from the crime scene," he said. "If the starting material is so deteriorated that a complete short tandem repeats (the newest and fastest technique used to generate a DNA profile) analysis cannot be performed, then the certainty of identification goes down."Also, if a rape victim had previously had consensual sex, it may be difficult or impossible to separate the DNA from the consensual partner from that of the rapist. Similarly, DNA from the female victim could complicate the analysis. In these cases, it may be possible to subtract the known DNA pattern of the victim from the perpetrator. How successful this subtraction approach is will be somewhat dependent upon on how different the signals are between the different people, Bishop said.He also noted that since DNA profiling has come into common practice, one of the biggest challenges has not been with the DNA itself but with irregularities among various laboratories and problems processing the evidence.

DNA gets criminal status

New York City policy of charging genetic material in lieu of a person raises technical and ethical concerns

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