It's also made everything go faster : before automatical fingerprint search was introduced ( AFIS ) , the police had to compare fingerprints with the database of the city ... Imagine having to compare 10,000 fingerprints ...
DNA ( how to sequence it ) has given the police unique caracteristics. But the best advantage of DNA, is that it is so easily found : for example, it the killer realises he has left a fingerprint, he will wide it off with the back of his hand ... but by doing it that , he might leave epithelials ... which are nearly invisible ...
What I mean, is that forensic science has made the use of science systematic, in a sense that processing a scene is now an extremely thorough job : you can't just have someone with a hunch ... you need to follow the fingerprints and DNA.