New tech could tell CSIs when fingerprints were made

A suspect says it on every forensics TV show ... "Of course my fingerprints were at their house, I delivered a package to them earlier this week!" Soon, though, that excuse may not be enough. Using a new technique, investigators could be better able to determine how many days ago fingerprints were left at a crime scene. The process was developed by Shin Muramoto and Edward Sisco, at the US-based National Institute of Standards and Technology (NIST). It involves using mass spectrometry to map the chemical composition of fingerprints, specifically to see which chemicals are present in what parts of the print.