Testimony from witnesses, objects (exhibits), or legal documents which one person uses to support and prove his case in court. There are strict rules about what evidence is allowed in court. Evidence from a witness, for example, is generally only allowed if the witness tells the court about things he knows directly. The court will generally not accept evidence from a witness who is just retelling what he heard from someone else. Objects which are being submitted as evidence must have been obtained following the proper procedure. For example, when police wiretap a telephone to record a conversation they must usually have a warrant from a court for doing this first, or it may be excluded from evidence.