Criminal Evidence

Evidence is used to prove or disprove a theory in criminal or other legal proceedings. The rules of evidence are very important in court proceeding to ensure only facts are submitted for consideration by a judge, jury, or other legal authority. Evidence is traditionally broken down into the following categories:

Real Evidence

To be admissible, real evidence, like all evidence, must be relevant, material, and competent. The relevance and materiality of real evidence are usually obvious. Evid. Code Ð'§ 1400; Fed. Rules Evid. 901.

Real evidence may be authenticated in three ways--by identification of a unique object, by identification of an object that has been made unique, and by establishing a chain of custody. The easiest and usually the least troublesome way to authenticate real evidence is by the testimony of a witness who can identify a unique object in court. If a witness who can establish an object's relevance to the case marks it with his signature, initials, or another mark that will allow him to testify that he can tell it from all other objects of its kind, that witness will be allowed to identify the object in court and thus to authenticate it. The third and least desirable way to authenticate real evidence is by establishing a chain of custody. Establishing a chain of custody requires that the whereabouts of the evidence at all times since the evidence was involved in the events at issue be established by competent testimony.

In that case, the evidence will be excluded unless another method of authentication can be used.

Demonstrative Evidence

Demonstrative evidence is just what the name implies--it demonstrates or illustrates the testimony of a witness.

When a photograph is authenticated by a witness who observed what is depicted in it and can testify that it accurately reflects what he saw, the photograph is demonstrative evidence. When it is authenticated by a technician or other witness who testifies about the operation of the equipment used to take it, it is real evidence and is, in the language of the courts, a "silent witness."

Documentary Evidence

Documentary evidence is often a kind of real evidence, as for example where a contract is offered to prove its terms. When a document is used this way it is authenticated the same way as any other real evidence--by a witness who identifies it or, less commonly, by witnesses who establish a chain of custody for it.

When dealing with documentary evidence, it is a good idea to ask yourself four questions:

1. Is there a parole evidence problem?

2. Is there a best evidence problem?

4. Is there a hearsay problem?

The parole evidence rule, which bars the admission of extrinsic evidence to vary the terms of a written agreement, is usually considered a matter of substantive law, not of rule of evidence. As has been noted above, documents can be authenticated the same way as any other real evidence. Evid. Code Ð'§ 1400, 1401, 1410-1416. Evid. Code Ð'§ 1402. Code Ð'§ 1417, authentication by evidence of a reply, Evid. Code Ð'§ 1420, and authentication by content, Evid. Code Ð'§ 1421.

In addition, some documents, such as certified copies of public records, official documents, newspapers, periodicals, trade inscriptions, acknowledged documents to prove the acknowledgment, certificates of the custodians of business records, and certain commercial paper and related documents are, to one extent or another, self authenticating under either California law or the federal rules. Evid. Code Ð'§ 1450 et seq., 1530 et seq., 1562; Fed. Rules Evid. We will cover the hearsay rule as a separate topic.

The best evidence rule provides that, where writing is offered in evidence, a copy or other secondary evidence of its content will not be received in place of the original document unless an adequate explanation is offered for the absence of the original. Evid. Code Ð'§ 1500 et seq.; Fed. Rules Evid. 1002. In California, testimonial and other secondary evidence of the document's content