Evaluating the Effectiveness of DNA Analysis on Property Crimes and Identifying a New Model for Outsourcing
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.
Figure 2: Results of profile evaluation for CODIS entry. Profiles were evaluated for CODIS eligibility and put into categories. 40% of profiles developed were entered into CODIS. Other profiles may not have been entered based on the case scenario, match to victim/elimination standard, or the results contained limited value or a complex mixture.
The remaining 77% of samples continued downstream for processing. Eligible DNA profiles were obtained for 23% of the tested samples and were uploaded into the Combined DNA Index System (CODIS) at the national, state, or local level. The primary reason for database ineligibility was that the samples yielded limited value or partial, uninterpretable DNA profiles. There were also unknown evidentiary samples that matched the victim or exclusionary standards. Of the 572 samples that were entered into CODIS, 235 were touch DNA sample types (Figure 2). Samples that were CODIS eligible and entered into the database were searched against the local, state, and/or national databases and generated a total of 232 hits, resulting in a 40% hit rate (Figure 3). Figure 4 shows the sample types resulting in database hits highlighting that the greatest number was contributed by touch DNA samples. This data unequivocally demonstrates the importance of collecting, submitting, and testing touch DNA evidence, and the potential benefits to law enforcement with regard to generating investigative leads for the ultimate purpose of identifying a perpetrator.
Figure 3: Breakdown of hits obtained per database type. CODIS eligible profiles were searched against the local, state, and national databases as appropriate resulting in 232 hits and a 40% hit rate. The majority of the hits occurred at the local and state level.
The PBSO FBU has noted that the benefits of processing property crimes are worth the costs. As a result of this comprehensive evaluation of Palm Beach County property crime data, the next logical step was to improve the efficiency of the outsourcing process to provide a method whereby every law enforcement agency has ownership and control of their cases. To this end, the PBSO FBU Direct DNA Initiative has been established in coordination with the BodeDirect Outsourcing program. In the past, law enforcement agencies have requested permission to submit property cases to the PBSO FBU, and upon approval, cases were submitted by the law enforcement agency to the PBSO Evidence Unit. The PBSO FBU Evidence Coordinator signed out the cases from the Evidence Unit, prepared a case manifest, and shipped all evidence. Upon completion of the DNA testing, all case file data and reports were sent to PBSO FBU along with the evidence. PBSO FBU would review all documents associated with the analytical data, upload any suitable results into CODIS, and issue a report to the law enforcement agency. The returned evidence would also be inventoried and then returned to the law enforcement agency. In total, the administrative and technical processes took approximately 12 months to complete.
The Direct DNA Initiative provides Palm Beach County law enforcement agencies a means to ship property crime cases directly to Bode. As a part of this initiative, PBSO FBU has introduced a training program that educates law enforcement agencies about what types of samples are CODIS eligible. Under this model, law enforcement agencies evaluate their own cases for eligibility prior to submission. Bode is then responsible for reviewing each case and interacting directly with the submitting law enforcement agency to resolve any questions prior to initiating DNA analysis. Upon the completion of analysis, the evidence and a court-ready report is returned directly to the law enforcement agency. If CODIS suitable results are obtained, a report and data will also be sent to PBSO FBU where the data will be reviewed and if eligible, the DNA profiles entered into the appropriate databases. Once uploaded into a database, PBSO FBU will directly issue a report to the law enforcement agency. It is estimated that the PBSO Direct DNA Initiative will decrease the total property crime processing time from 12 months to 4 or less. Palm Beach County law enforcement agencies can directly outsource burglary, theft, arson, larceny, shoplifting, and vandalism cases.
The streamlined process will allow consistent and faster turnaround times, reduce administrative burdens and evidence handling by the crime laboratory, and benefit citizens by allowing property crimes to be investigated in a more timely manner to ultimately solve crimes and reduce recidivism. Comprehensive metrics under the PBSO Direct DNA Initiative will be collected for a two year period in order to support and evaluate potential impacts.
Property Crime Case Example 1
Swabs were taken and submitted from bricks used to smash the steering column of a car. A single source, partial profile was obtained. The partial profile (14 of 16 markers) was suitable for CODIS upload and was entered into CODIS on November 14, 2011. On March 27, 2012 an arrestee sample was entered into CODIS and hit on the partial profile from the brick on March 31, 2012. The individual was arrested for assault and battery.
Property Crime Case Example 2
In early 2011 a rush turnaround case involving the sexual assault of a minor occurred. Mixture DNA profiles were obtained from items of evidence that were not consistent with the victim. The foreign profiles were entered into CODIS on January 19, 2011. There was an immediate hit from the local database with blood collected at a burglary scene from October, 2009. This investigation is still on-going.
- Bureau of Justice Statistics, “Criminal Victimization in the United States, 2007,” Table 82, http://bjs.ojp.usdoj.gov/content/pub/pdf/cvus07.pdf (accessed September 29, 2011) report update 5/11/2011 for 2008.
- Federal Bureau of Investigation, “Crime in the United States 2010: Burglary,” (Washington, DC: GPO, 2011), http://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2010/crime-in-the-... (accessed September 29, 2011).
- U.S. Department of Justice. Office of Justice Programs. National Institute of Justice. (2004). DNA in “Minor” Crimes Yields Major Benefits in Public Safety. In Short Toward Criminal Justice Solutions. November 2004 Issue. Retrieved April 17, 2012 from the Department of Justice Web site: https://www.ncjrs.gov/pdffiles1/nij/207203.pdf
- Ashikhmin, S., et al. (2008). Using DNA To Solve High-Volume Property Crimes In Denver: Saving Money, Lowering Crime Rates and Making Denver Safer, The Prosecutor, 42(3), 34 – 43.
Cecelia Crouse is the Crime Laboratory Director at the Palm Beach County Sheriff’s Office in West Palm Beach Florida.
Julie Sikorsky is the Forensic Biology Unit Manager for the Palm Beach County Sheriff’s office.
Amy Jeanguenat is Vice President, Director of Forensic Laboratory Operations at Bode Technology.
Teresa Vreeland is a Senior DNA Analyst with The Bode Technology Group.
Amelia Looper has been employed with the Forensic Biology Unit of the Palm Beach County Sheriff’s Office since 2010.