Heck v. Humphrey, 512 U.S. 477, was a landmark case in which the United States Supreme Court held that "in order to recover damages for allegedly unconstitutional conviction or imprisonment, or for other harm caused by actions whose unlawfulness would render a conviction or sentence invalid, a §1983 plaintiff must prove that the conviction or sentence has been reversed on direct appeal, expunged by executive order, declared invalid by a state tribunal authorized to make such determination, or called into question by a federal court's issuance of a writ of habeas corpus". From Wikipedia
