The ratio between two oxygen isotopes from precipitation reflects the distinctive features of the water consumed by persons living in or visiting an area. Water is the key to creating a “travel history” from an individual’s hair, because oxygen isotopes found in hair reflect the water that people drink in a given area; strontium isotopes are the preferred isotopes for water used in baths and showers. Brett Tipple, an IsoForensics research scientist, has received funding from the National Institute of Justice (NIJ) to develop databases and models that will assist in linking isotope ratios to the water in the geographical regions from which they come. Tipple is also developing a database and model to better predict region-of-origin information based on oxygen isotope ratios. As Tipple works to increase the specificity of isotope ratio information, IsoForensics continues to assist law enforcement investigators identify deceased victims by analyzing their hair to determine locations where they have been. Some case examples of such investigations are provided.