Case Studies of Preventable Crimes

DNA technology is evolving rapidly and many states are considering whether to expand DNA databases or invest in DNA casework investigations. In order to inform the discussion of these issues, NIJ commissioned an independent study to ascertain the size of and reasons for the nation's backlog of DNA evidence. The resulting report included the list of cases presented here. This list of cases is not exhaustive, does not identify the perpetrator or victim, and is not a reflection on the criminal justice agencies involved. These cases would remain unsolved if not for extraordinary detective work by dedicated criminal justice professionals in these agencies.

Case studies presented on this site are from an NIJ-funded independent study. Points of view or opinions in the resulting report are those of the authors and do not represent the official position or policies of the United States Department of Justice.

How Reducing the DNA Backlog Can Prevent Crimes

DNA databases can identify repeat offenders and help law enforcement solve a crime quickly—preventing additional crimes. However, the effectiveness of DNA databases is restricted by a number of factors:

• Collection of biological evidence from crime scenes.
• Submission of biological evident to crime labs.
• Turnaround time at crime labs.
• Lab policies on accepting and processing DNA samples.
• Size of the DNA database offender pool to which crime scene samples are compared.

It is impossible to determine how many crimes could be prevented by a more systematic use of forensic DNA testing, since one cannot count crimes that do not occur. These case studies nonetheless provide compelling examples of the power of DNA forensic analysis.

About The Case Studies

The case studies were developed through the assistance of investigators and prosecutors around the country, and reflect the following assumptions:

• State statutes requiring DNA from all convicted felons were feasible by 1990, the year Virginia enacted such a law.
• In addition to all felony offenses, state databases could include misdemeanor convictions that arose out of felony charges (many States have such requirements).
• A 30-day turn-around time for sample analysis is both desirable and possible, given sufficient resources.

When reviewing these cases, bear in mind that:

• Backlogs at crime laboratories are primarily the result of growing demand and limited resources.
• Law enforcement and prosecutors should not be expected to be able to identify offenders of unsolved crimes without full access to modern forensic techniques, including DNA and other tools.
• These case studies should be used to help inform discussion of policy and investment decisions. In each case, it should be understood that DNA technology has changed rapidly in recent years, as has what should be viewed as "preventable."
• States with multiple case studies should not be considered to have a particular deficit in DNA testing.

NIJ Funded Study

The cases are from National Forensic DNA Study Report and were developed using basic assumptions. For a full discussion on the review methodology that led to the conclusions presented here, see Section VI. "Forensic DNA and Crime Prevention." The report and case studies were prepared by Smith Alling Lane in partnership with Washington State University through the support of a grant awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice (Grant 2002-LT-BX-K 003). Points of view or opinions in this report are those of the authors and do not represent the official position or policies of the United States Department of Justice.