If they base the case entirely on one piece of evidence than they have already lost. Through programs like CSI, people are convinced that most of the evidence for a case comes from a lab and all they need is that one piece of evidence.
What really happens is the investigators have to answer the 5-Ws (who,what,etc) and they "build" a case against you. If they have one piece, then they can go fishing for the rest. This is why it's important to shut your month when talking to the police. Anything you say at this point can really open you up to all types of crap later. They'll twist your words around, become your friend, good cop/bad cop, mention friends and family and all other types of tricks to get you to talk. Believe it or not, criminals willingly give up testimony about themselves. Some guy in a lab with half a shoeprint isn't what wins the case, you do.
If all the prosecution has is one piece of evidence then a competent barrister can shred it to pieces. This guy's job is to create FUD, and lots of it. The less evidence the prosecution has the easier his job is. But what he/she can't do is fix anything you say in front of the police while he isn't there. This is why it's important to shut up and ask a lawyer first.
What really happens is the investigators have to answer the 5-Ws (who,what,etc) and they "build" a case against you. If they have one piece, then they can go fishing for the rest. This is why it's important to shut your month when talking to the police. Anything you say at this point can really open you up to all types of crap later. They'll twist your words around, become your friend, good cop/bad cop, mention friends and family and all other types of tricks to get you to talk. Believe it or not, criminals willingly give up testimony about themselves. Some guy in a lab with half a shoeprint isn't what wins the case, you do.
If all the prosecution has is one piece of evidence then a competent barrister can shred it to pieces. This guy's job is to create FUD, and lots of it. The less evidence the prosecution has the easier his job is. But what he/she can't do is fix anything you say in front of the police while he isn't there. This is why it's important to shut up and ask a lawyer first.