Sir Alec Jeffreys is not exactly a forensic scientist. However, his work on DNA profiling and fingerprinting is what paved the way for much of the analysis that is used today in modern forensic investigation. Jeffreys is a well-known geneticist, a professor at the University of Leicester in Britain. He had an epiphany about using DNA to identify people while studying X-ray images of a DNA experiment he was running in his lab. His techniques are used all over the world to catch criminals — in addition to resolving paternity disputes.