Available literature shows that habitual burglars commit on average greater than 230 high volume crimes such as burglaries annually, and that the potential to escalate to violent crimes is great. The Palm Beach County Sheriff’s Office Forensic Biology Unit (PBSO FBU) has taken a proactive approach to DNA testing the voluminous amount of property crime evidence submitted by Palm Beach County law enforcement agencies. Under this approach, the PBSO FBU has partnered with The Bode Technology Group, Inc. to test Palm Beach County high volume cases for possible DNA profiles, which may be entered into the DNA database and may generate investigative leads. In order to determine if the testing of evidence from Palm Beach County property crimes is efficacious and provide a positive impact on the case backlog, metrics were generated and evaluated from 1,286 cases processed between 2009 and 2011. Criteria included results by evidence type, database eligibility, database hit rates, and cost analysis. Data was obtained for over 3,400 samples. It was determined that the DNA processing of property crimes provided investigative leads by linking evidence to known offenders and to related crimes. As a direct result of this study, an initiative to streamline the process of performing property crime DNA testing has been designed and implemented. This model will serve to decrease the PBSO FBU backlog and case turnaround times by directly involving all Palm Beach County law enforcement agencies in the case submission process. It is important to note that this report concentrates on the tangible results from this study, and does not address intangible metrics such as the number of burglaries that were not committed because a perpetrator was arrested, the amount of money saved because burglaries were not committed due to arrests, the amount of money not spent on increased insurance rates, and others.
Although the PBSO FBU has regularly tested property crime evidence for DNA, historically testing was only conducted primarily if blood was left at the scene of the crime. Over the past twelve years, the volume of property crimes submitted to the laboratory has increased dramatically as different types of samples, such as touch evidence, have yielded DNA results. To meet the increased demand, the PBSO FBU has made a concerted effort to process these cases not only in reaction to the volume of property crimes that occur compared to violent crimes and the financial loss to residents when crimes against property occur, but also to prevent the potential recidivism of reoccurring offenders.
PBSO FBU property crime cases that are designated as eligible for outsourced DNA analysis include crimes from home, person, business, and vehicles through burglaries, larceny, arson, theft, shoplifting, and vandalism. These types of cases occur fifteen times more often than violent crime in the Palm Beach County area and are costly to both the victims and law enforcement agencies. According to a 2008 Bureau of Justice Statistics report,1 the total national economic loss to victims was $1.19 billion for violent crimes and $16.21 billion for property crimes. In 2010, the FBI estimated that the average dollar loss per burglary offense was $2,119 and the total lost for the year was an estimated $4.6 billion.2 Another concern for law enforcement is the safety of their residents since the analysis of CODIS hits has demonstrated high rates of recidivism and a general escalation in violence among reoffending criminals. An examination of the New York Police Department’s first 1,000 hits showed that most were linked to violent crimes, but of these, 82% of the offenders were already in the system for lesser crimes such as burglary.3 The state of Florida has also experienced similar results with approximately 52% of the violent crime (murder and sexual assault) database hits matching individuals who had prior convictions for burglary.3
Figure 1: Biological Sources of Evidence. Samples collected from property crimes are 90% touch evidence samples followed by sources of blood and saliva.
Pro-Active Strategy and Analysis of Outsourced Property Crime Data
Recently the Palm Beach County Sheriff’s Office Forensic Biology Unit compiled data from 1,286 outsourced property crime cases (from 2009 through 2011). Nearly 90% of the samples collected from these property crimes were classified as touch DNA while the remaining biological samples were predominantly blood and saliva (Figure 1). Touch DNA is defined as a biological sample obtained from an item or surface at the crime scene that the perpetrator may have touched, such as a weapon or tool, leaving behind small amounts of DNA. Touch DNA can be left on nearly anything with which a burglar may come into contact during the commission of a crime. With such a significant number of samples containing possible minute amounts of touch DNA, a validated quantification polymerase chain reaction assay was utilized to detect the amount of DNA present in a sample. For all samples resulting in a negative quantification value, processing stopped, which directly translated into cost savings over this time period. Through this “stop-at-quant” approach, approximately 23% of samples in this study were identified as having negative quantification results and therefore no further analysis was conducted.