The appeal judges states that a reasonable jury may have convicted BG without the GSR residue evidence and used that argument to block compensation for wrongful incarceration. However, without the GSR, there is no physical link between BG and the murder. The two eye witnesses described seeing a man of Mediterranean appearance who has never been traced. IMO, the investigators got tunnel vision on BG as the local weirdo.
So little physical evidence was left after the paramedics had trampled all over the scene, that it would be difficult to find solid proof linking anyone to the crime. However, the circumstantial evidence was substantial and far more than just "BG is the local weirdo."
A fibre found at the scene potentially matched a pair of his trousers, and a coat described by witnesses as having been worn by the killer matched BG's coat; a coat which had GSR in the pocket matching the ammunition used in Jill's murder.
Metropolitan Police experts narrowed down the type of gun to one of just a few unusual models. One of those models was listed in BG's ledger as a gun he owned, and he's also shown holding it in the mask photo--a photo he ludicrously claims isn't of him. That gun has disappeared without trace for no good reason. Without the ledger you might argue the gun he was holding in the photo wasn't his own. Without the photo you might argue the ledger didn't prove he *really* owned it. Both together pretty well prove he was in possession of one of the few rare weapons capable of firing the ammunition found at the scene.
BG was seen on Gowan Avenue earlier on the morning of the murder, and later attempted to create an alibi for himself. The attempt to form an alibi would be suspicious even in the absence of the clothing, the GSR, the gun, being seen on Gowan Avenue, etc.
It may only be circumstantial evidence and not solid physical evidence, but it's not randomly picking on the local weirdo, either. This "local weirdo" was the only person, out of the thousands of people they investigated, who actually fit the evidence they had. And he *is* a convicted dangerous predator who committed numerous armed attacks on women.
I'd also argue that in some of the pictures of BG taken around the time of the murder, he could be described as looking quite "mediterranean." It's hard to believe looking at him now, but in 1999/2000 his hair and goatee gave him quite a resemblance to George Michael--probably not accidental. George Michael was Greek, so "mediterranean" would have been an accurate description.
