13.1 - General Overview13.2 - Judicial Notice and Presumptions13.3 - Relevancy13.4 - Privileges13.5 - Witnesses13.6 - Opinions and Expert Testimony13.7 - Hearsay13.8 - Exhibits13.9 - The Use of Other Offenses and Acts13.10 - Selected Special Rules13.11 - Colorado Rules of Evidence


Witnesses must be competent to testify. Colorado law presumes that any witness who is ten years old or older is competent. A child who is under ten years of age may testify if the trial court determines that the child is capable of receiving just impressions of facts and of relating them truly to the jury. There are special rules regarding the competency of child witnesses in cases involving sexual assault and child abuse; these are discussed in section 13.12 below.

While it is uncommon, sometimes a trial court must make a determination as to whether an adult is competent to be a witness. It is even more rare for a trial court to exclude a witness as incompetent. Generally, we trust juries to evaluate the reliability and trustworthiness of witnesses, and expect counsel to bring to the attention of the jury any facts relating to those issues.

A witness must take an oath before testifying. Some witnesses object to certain oaths on religious or other grounds. In those situations, the oath requirement is satisfied if the witness acknowledges in some fashion the need to tell the truth and the fact that a failure to do so may be prosecuted as perjury.

One issue that arises frequently with regard to witnesses is how far a lawyer can go in attacking the character of a witness. The rules of evidence and the case interpreting those rules are complex, confusing and sometimes inconsistent. But there are certain general principles that apply and what follows is an effort to describe some of those general principles.

The first principle is that character evidence is generally disfavored. CRE 404 provides that evidence of a person's character is not admissible to prove that the person acted in conformity with that character on a particular occasion. Thus, for example, evidence that a person is a drinker is generally not admissible to prove that the person drove under the influence of alcohol on a particular night. Evidence of how much the person drank that night is, of course, relevant, but the person's general drinking habits are not. This rule is premised on the notion that a person should be evaluated on what the person did pr did not do - at the time in question, not on what the person may or may not have done in the past.

The second general principle is that character evidence concerning the truthfulness of a witness is much more likely to be admitted than other types of character evidence. Character is a broad term. One specific aspect of character is character for truthfulness of a witness. Generally, a witness' character for truthfulness is relevant. If a witness has a reputation in the community for being a liar, that reputation can generally be admitted as evidence. If someone has a personal opinion about the truthfulness of a witness, that opinion can generally be admitted. However, this rule does not allow a witness to testify that another witness is, or is not, telling the truth at trial. Nor does the rule authorize the use of specific instances of conduct as proof of character; the use of specific instances of conduct is discussed in section 13.9 below.

A third general principle is that character evidence may be admissible in certain situations because it is part of the charge or defense in a case. For example, if a criminal defendant who is charged with assault claims that she acted in self-defense, she may be entitled to introduce evidence of her own character for peacefulness or the character of the alleged victim for aggressive behavior. Once a defendant does so, the prosecution may then be entitled to rebut that evidence with other testimony that contradicts the characterization of the defendant or the alleged victim.

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