Forensics evidence is almost always circumstantial. For your example - If everyone wears wool sweaters except one person wearing poly microfibre, what is the i

Forensics evidence is almost always circumstantial. For your example - If everyone wears wool sweaters except one person wearing poly microfibre, what is the inference? The first rule that is taught in forensics is that every interaction leaves a trace of some sort. The poly microfibre showed up at the scene. How did it get there is now a different type of forensics and where lawyers step in. The prosecutor will insist because the poly microfibre owner was there, while the defense lawyer will insist, there was a party the night before and everyone was rubbing against each other, the poly microfibre wearer and the wool sweater wearers. It can be anyone.