(quoted from post at 18:00:38 12/18/18)
(quoted from post at 10:56:49 12/18/18) There is a such thing as "chain of evidence." If you found that pieced of tape in the car, you should have left it right where it was. In order to be admissible in court, it would have to be witnessed by an officer of the law, processed, and chain of custody would have to be established. Just taking a piece of tape with a fingerprint on it to the police proves nothing. It could have come from anyplace. As evidence, it has no value.
Evidence admissibility in criminal cases is a minefield. Whole weeks are spent by both sides, and a judge may delay a case for days deciding on evidence. It is a very fractious part of law.
An example. Suppose you rent a house to a guy, and after he moves out you find a gun in the attic. You take the gun(personally) to the police, and they test fire it, finding it matches the gun used in the Zodiac Killer crime spree. They locate the previous tenant, and can tie him to time and place of the Zodiac killings, and match a partial print to the tenant. He is arrested all based on the gun given to the cops. I can tell you that any DA will fight tooth and nail to have it admitted in the trial.
Was it all fruit of a poisonous tree? Was it honest citizen doing honest work by giving the gun over to the police as he cleaned house? Only thing I can guarantee is that the evidence hearing will last for days, or weeks, and it could go either way.