>> sean: it is a disturbing phenomenon in today's courtroom known as the csi effect raising standard and burden of proof for prosecutors and acquittal rate for likely guilty defendants all over america. >> many potential jurors expect crime scenes to be portrayed the way they seem to be on tv. with cops arriving at a murder scene, finding the victim and immediately starting to gather a treasure trove of evidence. they think detectives should find the dna and er principles of the guilty party. >> in lots of courtrooms where dna doesn't appear, the prosecution doesn't come up with that magic bit of forensic evidence, jurors say then the guy must be not guilty or at least we have reasonable doubt. >> sean: is the so-called csi effect to blame for the jury's