Wolfram Meier-Augenstein, an analytical chemist at James Hutton Institute in Dundee, Scotland, has developed a procedure to determine where unidentified victims of crime have lived or traveled. He measures the stable isotope ratios of carbon, oxygen, hydrogen, nitrogen, and sulfur found in samples of the victim's hair, teeth, nail, and bone. He has revealed that checking these elements' isotope ratios against databases that contain global isotope abundances can provide investigators with the victim's probable trajectory during his or her last weeks, months, and years before death. The use of stable isotope measurements to help identify human bodies is part of an emerging field, called isoscapes. Identification by isoscapes is based on the idea that a person's tissue holds an isotope ratio fingerprint that derives from the isotope ratios of food, water, and air, which vary with geography.