That can be true for an individual piece of evidence, but when the bulk of the evidence in a case is circumstantial in nature, it is the totality of the evidence that is to be weighed, not the individual pieces separately. Something called Hodges' Rule is to be applied, basically it can be paraphrased as "the bulk of the evidence must be consistent with the accused being the perpetrator, and be inconsistent with the perpetrator being any other person."
You can see a discussion of this precept here:
http://www.duhaime.org/LegalDictionary/H/HodgesCase.aspx
What we're seeing is the weight of the evidence tipping slowly but surely towards the consistent with the guilt of the accused direction and simultaneously inconsistent with the likely guilt of any other persons (unless one wants to speculate about alien invasions). Some components of the evidence may be discarded from consideration by the jury, individually or collectively, but it's looking more and more as though Hodges' Rule is going to come down on the side of "inconsistent with any other explanation."
Of course the defense could introduce new and game-changing evidence but I'm not anticipating any such development.