Fleeting Fingerprints May Yield Powerful New Tools

SAN FRANCISCO--The kidnapping and murder of 3-year-old Katie Lynn Lee in 1993 could leave a lasting legacy to law enforcement: methods to obtain children's fingerprints before they evaporate from crime scenes and to develop chemical "profiles" of criminals. The findings, reported here this week at the annual meeting of the American Chemical Society, may even lead to a new approach to diagnosing illnesses.

Police investigating Lee's disappearance in Knoxville, Tennessee, failed to find evidence of her fingerprints despite eyewitness accounts placing her at the scene. The police asked Michelle Buchanan, group leader for organic mass spectrometry at the U.S. Department of Energy's Oak Ridge National Laboratory in Tennessee, to take a crack at solving the mystery.

Buchanan's team used gas chromatography and mass spectrometry to compare fingertip chemicals from dozens of children aged 4 to 17 with those from adults aged 19 to 46. Children's fingerprints, they found, evaporated quickly from warm surfaces because they are loaded with volatile fatty acids. After puberty, however, sebaceous glands begin to secrete heavier, less volatile, long-chain alkyl esters that the carbonaceous fingerprinting dust easily picked up.

Buchanan's team has identified certain compounds, such as squalene, common to the fingerprints of children as well as adults. A system for detecting unique fingerprints from these chemicals could be developed in 3 to 5 years, estimates Knoxville detective Art Bohanan. "We've identified the problem, and now we need a solution," he says. In the meantime, Bohanan says that investigators should dust for children's fingerprints immediately at a crime scene and keep key evidence under refrigeration.

Buchanan's team has found a wealth of other insights into body chemistry hidden in fingerprints. For instance, they were able to measure cholesterol, nicotine, and hormone levels in subjects' fingerprints. "Down the road, maybe police will be able to say, 'This fingerprint was left by a 34-year-old male who smoked marijuana and had high cholesterol,' " says team member Stephen Jarboe of Transylvania University in Lexington, Kentucky. Buchanan says she hopes the findings will spur researchers to develop systems for profiling criminals and diagnosing diseases without surgery.