NCJ Number
223866
Journal
Journal of Forensic Sciences Volume: 53 Issue: 4 Dated: July 2008 Pages: 797-801
Date Published
July 2008
Length
5 pages
Annotation
Using data from the police force in Northamptonshire (United Kingdom) for January-December 2006, this study identified factors other than timeliness that might influence opportunities to convert DNA material recovered from a crime scene into a DNA profile, and from a DNA profile into a DNA match.
Abstract
The study found that the conversion of DNA material recovered from a crime scene into a DNA profile was significantly dependent on the accreditation of the crime-scene examiner (CSE) who performed the recovery for all five DNA sources examined (blood, cigarette end, saliva, chewing gum, and cellular). The ability of the CSE to recognize and properly recover DNA-rich material from the crime scene was critical in determining whether or not a DNA profile emerged from the investigation. The nature of the source for DNA was also significant in determining whether or not a DNA profile could be produced. Blood produced an efficient conversion of over 90 percent. The three sources of saliva produced the next three most efficient conversions to a DNA profile. Cellular DNA was the least efficient, since it requires recovery from a potential contact area that contains no obvious DNA material. The aforementioned conversions will be influenced by the occasional recovery of material in which DNA was originally present but has become so degraded that it no longer produces a DNA profile. The CSE has no control over the quality of the sample other than to decide not to recover it. None of the predictors examined showed any significance in influencing the conversion of a DNA profile to a DNA match. The analysis involved the processing of approximately 1,500 samples of DNA material recovered from the property crime offenses of residential burglary, commercial burglary, and theft of motor vehicles. The conversion of these DNA samples into DNA profiles and then into matches with offender profiles in the United Kingdom’s National DNA database was considered in terms of the ease with which CSEs can recover DNA-rich samples from various sources, the location of the DNA at the crime scene, and its mobility. 3 tables, 3 figures, and 12 references