Fingerprints – including those left at the scenes of crimes – contain chemicals that can be analyzed. These chemicals disappear over time, so you would think that researchers could easily sequence their placement. But the trick is not to just analyze the amounts of the chemicals (a complex mix of cholesterol, amino acids, and proteins), but to analyze their proportions relative to each other. A team from the Netherlands has cracked the code and is now moving on to determining from those fingerprint chemicals a suspect's drug or food consumption. Fingerprint researcher Marcel de Puit of the Dutch Forensic Institute says of their technique, which is currently undergoing testing, "It's not quite the Holy Grail of fingerprinting, but it's a very important discovery."