Demonstrative Evidence - Mechanics of Use

Mechanics of Use

In American jurisprudence, demonstrative evidence, like any other kind of evidence must be relevant. At this point the proponent of the demonstrative evidence can either try to get the evidence admitted into the official record of the case or can choose to use the evidence as merely a prop. If the proponent of the evidence wants to have the evidence included in the official record of the case, the proponent will first ask for the evidence to be marked by the court for identification purposes. After the evidence is marked for identification, the proponent of the demonstrative evidence must lay a foundation. It is at this time that the relevancy of the demonstrative evidence is usually challenged. Laying of a foundation explains how the demonstrative evidence relates to the facts of the case and establishes the evidence's authenticity. Once the foundation is laid, the proponent may ask to officially move the piece of evidence into the record where it is marked as a full exhibit. If the evidence is marked as a full exhibit the jury may refer to the evidence during deliberations and in most jurisdictions the jury may examine the evidence during deliberations. If the evidence is not marked as a full exhibit, the jury cannot do these things. As a matter of courtesy, the proponent of the demonstrative evidence generally shows the piece of evidence to the opposing party before marking it for identification purposes. In criminal cases certain kinds of demonstrative evidence are subject to mandatory disclosure under the case law governing discovery. See Brady v. Maryland.