New technique can determine when a fingerprint was made

New Scientist : A new method of analyzing a fingerprint could reveal not just its pattern but also when it was made. Many methods, including dusting, chemical agents, and atomic force microsopy, have been developed to capture fingerprints. All of them have their limitations. Now Robert Prance and colleagues at the University of Sussex in Brighton, UK, have developed a way to capture fingerprints by examining the small amount of static charge left behind when a finger makes contact with an insulating surface such as plastic or glass, writes Wendy Zukerman for New Scientist. By measuring the static charge repeatedly over a period of two weeks, the researchers, who have published their results in Forensic Science International, found that the charge decayed over time and, therefore, the measurements could be used to determine when a fingerprint was made. The technique could be used in forensics to determine when a crime was committed or to narrow a list of suspects. There are limitations, however: It won’t work with prints left on a conducting material, such as a metal bullet casing.