The spoliation of evidence is the intentional, reckless, or negligent withholding, hiding, altering, fabricating, or destroying of evidence relevant to a legal proceeding. Spoliation has three possible consequences: in jurisdictions where the (intentional) act is criminal by statute, it may result in fines and incarceration (if convicted in a separate criminal proceeding) for the parties who engaged in the spoliation; in jurisdictions where relevant case law precedent has been established, proceedings possibly altered by spoliation may be interpreted under a spoliation inference, or by other corrective measures, depending on the jurisdiction; in some jurisdictions the act of spoliation can itself be an actionable tort.
The spoliation inference is a negative evidentiary inference that a finder of fact can draw from a party's destruction of a document or thing that is relevant to an ongoing or reasonably foreseeable civil or criminal proceeding: the finder of fact can review all evidence uncovered in as strong a light as possible against the spoliator and in favor of the opposing party.
The theory of the spoliation inference is that when a party destroys evidence, it may be reasonable to infer that the party had "consciousness of guilt" or other motivation to avoid the evidence. Therefore, the factfinder may conclude that the evidence would have been unfavorable to the spoliator. Some jurisdictions have recognized a spoliation tort action, which allows the victim of destruction of evidence to file a separate tort action against a spoliator.
While spoliation of evidence most often shows up in civil cases with allegations that the defendant allowed videos, photos or physical evidence to be destroyed, spoliation is also an issue where a person claims he has been injured by a defective product which he then discarded or lost. In that circumstance, the defendant manufacturer or distributor may move to dismiss the case on the basis of spoliation (instead of just having to rely on the plaintiff's usual burden of proof, the argument being that any testimony of plaintiff's witnesses would not overcome the spoliation inference born of the lost evidentiary value of the missing product itself).
Finally, some states have case law or code sections allowing parties to recover civil damages for the act of spoliation itself. Some states only allow it against third parties, where an insurance company allows a car involved in litigation to be crushed for example. Each state handles the issue in their own manner and case law is constantly evolving.