trace evidence was in the vacuum cleaner. One orange fibre with her body was consistent with about 200 in his house and 20 in his SUV (none in his RV), while 21 blue fibres with her body were consistent with 10 in his house and 46 in his RV (none in his SUV). Contrary to media reports, only a few items from her house were tested so that can't be excluded as the source. In particular, the clothes of Danielle and her family during the cookie sale were not determined and eliminated. There were apparently two different types of the orange fibres, dull and very bright (so the number which matched might have been much less than 200). There were red fibres with her fingernails, and many other fibres with her body, which could not be matched to his environment. The only non-Danielle hair found with her body wasn't his, nor was any desert sand reported with the body, and no soil or vegetation from the dump site was reported on his shoes, laundry, shovel or RV. To explain why so much expected evidence was missing, the prosecution argued that he went on a cleaning frenzy, and tossed out evidence. Application in Information Security Locard's Principle also holds in computer forensics, where committing cyber crime will result in a digital trace being left behind. References External links Evidence Dynamics: Locard's Exchange Principle & Crime Reconstruction, W. J. Chisum, B. E. Turvey Fuller, John. (17 June 2008) "How Locard's Exchange Principle Works", HowStuffWorks.com. Forensic science Principles