Right. In the right circumstances fingerprint evidence is reliable. The law enforcement agencies don't mention much about what those circumstances are, though. Basically, if a good, clean fingerprint can be found then the chances of a false match are minuscule. But those chances rise fairly sharply if there's only a partial fingerprint available.
From what I can gather a complete DNA match is impossible, with the possible exception of identical twins. However, many of the existing DNA tests only perform partial matching, and the possibility of a match again rises sharply.
In the UK the police have been using DNA matching for quite a while, and there are regular stories of people being charged with old crimes, after they've given a DNA sample for some unrelated offence. Most such people end up convicted of the old crime. (I have some worries over that. How could anyone be expected to come up with an alibi after several years have elapsed? Can *you* remember what you were doing on one particular evening 15 years ago?)
One such person *was* able to prove he was innocent of the crime, though. Records showed that he was in prison at the time of the offence. The DNA evidence had already shown a match. There was some hasty reorganization after that in the DNA labs, and they started trying to identify the DNA with greater precision. It's now foolproof, apparently. I imagine that they'll stick with that view until another fool comes along with a cast-iron alibi.
Graeme Thomas