DNA Databanking: Selected Fourth Amendment Issues and Analysis

Emily C. Barbour
Legislative Attorney

Over the past few decades, state and federal lawmakers have promoted the development of databases containing DNA (deoxyribonucleic acid) profiles for individuals who are under the supervision of the criminal justice system due to their known or suspected involvement in a felony or other qualifying crime. Congress has demonstrated concern toward some aspects of DNA databanking by requiring expungement of a DNA profile in certain circumstances, prohibiting most non-forensic uses of DNA profiles and databases, and restricting familial searching. However, in general, Congress has taken a supportive attitude toward DNA databanking and has incentivized the development, expansion, and integration of DNA databases.

As DNA database programs have widened in scope and grown in numbers, their consistency with the Fourth Amendment’s prohibition on unreasonable searches and seizures has increasingly been challenged. In the context of compulsory DNA collection, courts have widely upheld laws mandating the collection of DNA from persons who were convicted and are subject to the penal system’s custody or supervision. Far fewer cases have addressed whether DNA collection from arrestees is also constitutional. The two federal circuit courts of appeals to hear the question upheld the mandatory DNA profiling of indicted arrestees, but no federal court has assessed the constitutionality of profiling arrestees in the absence of a judicial finding of probable cause.

Courts have generally upheld the use and permanent storage of a lawfully databanked DNA profile. However, not all courts agree that any post-conviction use of those profiles is constitutionally acceptable. In particular, observers are now raising questions about the Fourth Amendment consistency of using databases for non-forensic purposes and for familial searching—that is, using the DNA databases to locate potential relatives of an unidentified suspect. Currently, these concerns are largely confined to the scholarly literature—they have not come before a federal court—and are primarily centered on state database programs. Unlike some state DNA databases, the National DNA Index System (NDIS) and the Combined DNA Index System (CODIS) can not be used for either non-forensic research or intentional familial searching. However, the increase in states that authorize familial searching suggests that it may not be long before the constitutionality of familial searching comes before a federal court.

As these issues percolate up to the courts, new advances and revelations in the science of forensic analysis and databanking may have potentially significant legal implications. Several courts have suggested that new forensic techniques and scientific findings would require them to reevaluate their legal conclusions and analysis. In particular, research into the scope and nature of the information revealed by the “junk” DNA used in forensic analysis may alter how courts measure the intrusiveness of DNA profiling if it suggests that “junk” DNA reveals more sensitive information about its source than scientists previously thought.


Date of Report: August 16, 2011
Number of Pages: 23
Order Number: R41847
Price: $29.95

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