That would be the wrong approach. First big problem is that cops or anyone else can wear gloves. Second, you aren’t really trying to prove who owned the drugs. You would be interested in proving that the space in which the drugs were found previously did not contain the drugs before the cops “found” them. That’s why bodycams are super important. Most evidence tampering cases boil down to “spot was clearly empty before cop mysteriously produces drugs from the same spot”