Television shows scramble forensic evidence

Yeah, I admit I like the CSI shows particularly the original. It seems that shows like CSI are so well-known that jurors in crime investigations believe that Forensics experts can do no wrong:

"Jurors who watch CSI believe that those scenarios, where forensic scientists are always right, are what really happens," says Peter Bull, a forensic sedimentologist at the University of Oxford. It means that in court, juries are not impressed with evidence presented in cautious scientific terms.

And criminals use the shows to try to mask potential evidence of their crimes though in many cases, they're not very successful:

Rutty tested just how easy contamination is by asking a volunteer to walk around a sterile room and repeat a phrase. Rutty was able to retrieve the subject's DNA even though the man had been in the room for only a few seconds. Contamination occurred even if the subject was wearing a face mask of the kind used by crime scene investigators.