A court of appeals recently dealt with an issue that lawyers in litigation have to struggle with from time to time: "spoliation of evidence." Spoliation of evidence is where one side of a litigation dispute destroys or alters evidence that the other side needs for its case.
As a matter of fact, in addition to the severe sanctions a trial court will likely impose on a party for such conduct, the act of spoliation of evidence all by itself gives rise to a specific separate cause of action against a party who does it - including a party who was not initially involved with the case.
Stated another way, if a defendant is being sued (or about to be sued), and (for whatever reason) a third party alters or destroys evidence that could be used in that lawsuit, that third party can be independently sued by either the plaintiff or the defendant for that conduct. Most of the times however, the party who is altering or destroying the evidence is already a party to the lawsuit and is just doing this type of conduct to cover its proverbial tracks. We have been involved with litigation where spoliation of evidence has reared its ugly head on the other side of the table. Very very nasty consequences.