paparo has reviewed thousands of print-related cases in his career. he is often called upon to testify in court as an expert in the field. >> during the course of the investigation, over a two-week period i was given well over a dozen fingerprints to look at. i take all those fingerprints and i go through each one individually. >> it's an intricate process but one that's proven successful to law enforcement professionals for decades. robert epstein is a federal public defender who has taken a special interest in the science of fingerprinting. >> i think from tv, people may have the impression that the computers can make these type of identifications. it just doesn't work that way at all. >> while computers can help identify a potential match, it's up to the fingerprint examiner to make an expert judgment. >> it's entirely dependent upon the human's perception and the human's ability to compare the print. >> it comes down to the experience of the investigator reviewing the prints to know the awesome power that he holds in his hands when he's reviewing