The hearsay rule states that testimony given as to the facts in a case must come from a person who has seen, heard, tasted, or smelled the evidence. For example, in most cases a witness cannot testify about an event he was told about by another person; this would be hearsay evidence and not admissible in court. One exception to the hearsay rule is the dying declaration, in which the dying person has accused someone of a crime. Before this evidence can be submitted to the court, three requirements must be met: the statement must be related to the case, the person making the statement must be dying and later dead, the the dying person must believe he is dying. Examples of dying declarations that would be acceptable as evidence are given. In addition, rules of evidence applicable to crimes of moral turpitude, and crimes at common law such as murder, burglary, or rape, are discussed. For example, in prosecuting such crimes, attorneys will attempt to attack the defendant's credibility by revealing their prior convictions. However, prosecutors cannot present direct evidence of unrelated crimes previously committed by the defendant except in cases where the crimes were closely linked in time and circumstances and malice was evident. Other rules of evidence discussed deal with prejudicial statements, admissibility of crime scene sketches, and the use of notes in court.