By the time the Nature article had appeared in 1994, confirming the scientific community’s acceptance of DNA typing, law enforcement agencies had already accepted the validity of the technology and moved to incorporate it into their forensic toolboxes. One of the most powerful systems for using DNA profiles was the DNA database. A DNA database is simply a library of DNA samples taken from individuals and crime scenes and stored in some central location. The database is used to compare DNA samples collected at the scene of a crime or taken from people arrested for crimes with samples from known felons. It is also used to help solve so-called cold cases, which law enforcement officials have been unable to solve by any other means.

The FBI established the first DNA database in the United States in 1990 as a pilot project serving 14 state and local law enforcement laboratories. The success of that program led to the passage of the DNA Identification Act of 1994 (Public Law 103-322) that mandated the creation of a Combined DNA Index System (CODIS), a collaborative effort involving the FBI and state and local law enforcement agencies. The system is a three-tier program that makes possible the fl ow of information back and forth from local agencies (local DNA index systems; LDIS) to state agencies (state DNA index systems; SDIS) to the FBI (the National DNA Index System; NDIS), and back again.

The development of CODIS took place slowly, at least partly because all 50 states had to pass their own enabling legislation. The system became completely operational on November 14, 1998, although by that time CODIS had already been used to solve a number of crimes in participating states. (The first DNA database anywhere in the world was established in the United Kingdom on April 10, 1995.) As of 2007, CODIS contained DNA samples taken from more than 4 million convicted offenders and more than 160,000 crime scenes. The system had produced nearly 42,000 matches associated with about 43,000 criminal investigations in 49 states and two federal laboratories.

The success of CODIS tends to mask some ongoing issues about DNA databases. There is usually little dispute about the collection and storage of DNA samples from individuals convicted of violent crimes or from crime scenes. The problem is that some law enforcement officials and politicians have called for the expansion of DNA databases to include individuals who are arrested or accused of crimes, even if they are not prosecuted or convicted of those crimes. Former British prime minister Tony Blair was an especially enthusiastic proponent of expanding DNA databases to include anyone remotely involved in crime. In 2000, for example, he recommended increasing the U.K. DNA database to include “virtually the entire criminal population.” That category would have included “anyone who is arrested on suspicion of any ‘recordable’ offense (including being drunk in a public place, begging, or taking part in a prohibited public procession), even though DNA evidence is usually not relevant to the investigation.”40 Similar proposals have come from a number of high-ranking officials in the United States. In 2003, President George W. Bush proposed expanding the U.S. DNA database to include juvenile offenders and individuals who have been arrested for, but not necessarily tried for or convicted of, a crime. The likelihood was that the DNA database was likely to increase even further in the future. According to one official, Deborah Daniels, then assistant U.S. attorney general for justice programs: “DNA is to the 21st century what fingerprinting was to the 20th. The widespread use of DNA evidence is the future of law enforcement in this country.”

The argument in support of expanding DNA databases is that there is no way of knowing in advance who is going to commit a violent crime. If everyone’s DNA is on file, solving an unexpected crime is likely to be much easier since critical evidence is already available in some DNA database. In addition, many proponents of expanding databases offer a familiar argument, namely that individuals who are not criminals should have no concern about providing DNA samples for law enforcement agencies.

On the other hand, suggestions for DNA databases that go beyond convicted criminals raise concern among civil libertarians. In the first place, a number of individuals accused of, suspected of, or arrested for crimes are never convicted of those crimes. They may be completely innocent persons who become enmeshed in the criminal justice system. Should their DNA become part of a database? And, if so, should the DNA of all innocent people be collected?

Also, critics ask, is it really necessary or helpful to expand DNA databases to include those convicted of nonviolent crimes, such as burglary, fraud, petty theft, or vagrancy? If so, should everyone convicted of a misdemeanor or felony be included in a DNA database, or are only certain types of crimes serious enough to be considered; if so, which crimes?

In an effort to solve this dilemma, Attorney General Janet Reno appointed a commission in 1998 to study DNA databases. That commission, the National Commission on the Future of DNA Evidence, consisted of scientists, law enforcement officials, prosecuting and defense attorneys, and judges. In its final report, the commission reviewed the scientific, political, legal, and ethical issues posed by DNA databases and identified yet another problem surrounding the expansion of such programs. Thus far, the commission discovered, DNA laboratories had been unable to keep up with the job of typing preexisting DNA samples of convicted felons. At the time the commission report was issued, nearly half a million DNA samples were still waiting to be typed and an equal number of convicted felons were waiting to have their DNA taken. Under these circumstances, the commission wrote, any proposals for the expansion of DNA databases were, for all practical purposes, moot.