Experts admitted as much regarding the trouser fibre. I assume clothing owned by other people known to Jill would have been compared and ruled out, along with clothing worn by those known to have been on the scene such as the neighbours, paramedics, investigators etc. It was one more circumstantial piece of evidence against BG; Nick Ross lays it all out in his article (
Link) much more thoroughly than I can. Circumstantial, but to me very compelling. As I said before, the bar for conviction is high. I believe BG is most likely guilty, but as a juror, I don't think I could convict based on this evidence either. What you believe or even what you know, and what you can prove, are often two different things.
I've known about the evidence in the case for about 20 years, but what has really made me believe he's guilty is watching and listening to *BG*. He's a manipulative, predatory liar IMO, and I'd feel that way about him even if he didn't kill Jill Dando.
To this day, BG is still lying about the photo of him wearing a gas mask and holding a gun consistent with the one believed to have been used in the shooting. Where did that gun go, and why does BG have no explanation for it other than a blanket denial of the obvious? At the time of his arrest he not only denied killing Jill, he denied knowing who she was completely; ridiculous given how ubiquitous she was at the time, and also given the celebrity magazines found in his home. His lies are so flagrant and unnecessary that they make him look more guilty. His desperate efforts to get local people to give him an alibi are likewise incriminating.
How much would you expect to find if a total stranger walked up behind you, quickly pushed you down with one hand, pushed the barrel of a gun against your head with the other hand, and immediately walked away again?
I'd expect there to be more evidence of Jill on the killer than evidence of the killer on Jill. Even if BG is the killer, his clothing wasn't examined for over a year.
Even in a best-case scenario I'm not sure there would have been much to find, and this was far from a best-case scenario.