DNA and Property Crimes
DNA evidence has become an increasingly powerful tool for solving crimes. The cost of performing DNA analysis of biological evidence collected from crime scenes is going down, new technologies are more widely distributed and the criminal justice system is learning to use DNA evidence more effectively.
For years, law enforcement officials have used DNA to solve violent crimes, such as homicide and sexual assault. Now, research reveals that collecting DNA in property crimes, such as burglaries, is cost-effective and dramatically increases the number of suspects identified.
The DNA Field Experiment
In June 2008, NIJ released the results of a five-city field study that looked at the effectiveness of performing DNA analysis on biological evidence collected from property crime scenes.
The DNA Field Experiment was a collaboration between NIJ and local law enforcement agencies—police, crime labs and prosecutors—in five communities: Los Angeles, Topeka, Denver, Phoenix and Orange County (Calif.). The purpose of the study was to determine whether it was cost effective to use DNA in the investigation of ordinary property crimes.
Major Findings from the DNA Field Experiment
Findings of the study, averaged across the five jurisdictions, were that when DNA evidence was collected at property crime scenes:
- Suspect identifications and arrests doubled.
Twice as many property crime suspects were identified and arrested when DNA evidence was collected (in addition to fingerprint evidence) compared to a traditional property crime investigation.
- Cases accepted for prosecutions doubled.
More than twice as many cases were accepted for prosecution when DNA evidence was processed than when it was not.
- The suspects arrested through DNA identifications were more dangerous.
DNA arrestees had double the number of prior arrests and double the prior convictions as those arrested through traditional investigations.
- DNA was twice as effective in identifying suspects as fingerprints.
In cases where both fingerprint and biological evidence were collected, more suspects were identified via the FBI's Combined DNA Index System (CODIS) than were identified via the FBI's Automated Fingerprint Identification (AFIS) system.