Some of the chemicals found in fingerprints come from things people have handled; others are made by the body. The metabolites found in sweat are not well understood, but it’s likely that they differ with age, gender, and other characteristics that would help identify suspects, says Cooks. Mass spectrometry could help uncover these variations. And Winograd says that the chemicals found in fingerprints might also provide information about drug metabolism and other medically interesting processes. Winograd, Cooks, and many others have recently begun using mass spectrometry to study the molecular workings of cancerous tissues and cells. Mass spectrometry might reveal that diagnostic information exists in sweat as well, says Winograd.

However, Morgan cautions that the work is preliminary and that the technology may prove too expensive for widespread adoption by law-enforcement agencies. Indeed, Cooks has not developed a commercial version of the fingerprint-analysis instrument.

“They have a long way to go,” agrees Michael Cherry, vice chairman of the digital technology committee at the National Association of Criminal Defense Lawyers, who has extensive experience interpreting fingerprints. He says that Cooks’s group has demonstrated the potential of the technology. However, after examining some fingerprint images made using mass spectrometry, Cherry says that the technology will require further development to be good enough to hold up in court.