Exculpatory Evidence
Exculpatory Evidence is evidence that supports a defendant's innocence. In the American Legal System it is required that all evidence be made available in the court of law. In the Sixth Amendment of the U.S. Constitution the rights of a person to "be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor" are all enumerated in the founding document, which is The Supreme Law of the Land (Article VI.). That includes all evidence. It is a crime to hide evidence, or disallow it from being made available when it is pertinent and directly connected.