Assessing Witness Competency in Criminal Trials

In criminal law, witness testimony plays a central role in establishing facts and determining the outcome of a case.  However, not all potential witnesses are deemed competent to testify, and therefore their potential testimony may be deemed entirely inadmissible.  Both California Evidence Code sections 700-704 and the Federal Rules of Evidence Rules 601-606 establish the framework for assessing witness competency in criminal trials.  

In California, witness competency is governed by Evidence Code Sections 700-704, which set forth the general criteria for witness competency.  A witness is generally presumed competent unless they fail to meet one or more of the following requirements:

Perception: Section 701 states that the witness must have personal knowledge of the matter they are testifying about.  In other words, they must have perceived the events through their senses or have been aware of them through reliable means. 

Communication: Section 701 also requires that the witness be able to communicate their perceptions to the court.  This includes the ability to understand questions and provide coherent answers. 

Memory: Section 702 states that the witness must be able to remember the events they are testifying about.  

Witness Unable to Communicate: In an attempted murder trial, the victim is in a vegetative state and has been unable to communicate with anyone since before the attack.  The victim would likely be deemed incompetent to testify, based on his inability to communicate his perceptions to the court. 

Amnesiac Witness: In a criminal trial involving an alleged assault, a potential witness suffered a head injury during the incident and now has amnesia, which has affected their memory of the event.  This witness may be found incompetent under California law, as they lack the required memory to provide relevant testimony. 

In federal criminal proceedings, witness competency is addressed in Rules 601-606 of the Federal Rules of Evidence.  These rules closely mirror the California provisions, establishing general criteria for witness competency. 

Personal Knowledge: Per Rule 602, witnesses must have personal knowledge of the matter they are testifying about and must have perceived the events or facts they are discussing. 

Oath or Affirmation:  According to Rule 603, witnesses must take an oath or make an affirmation to testify truthfully, and failure to do so renders the witness incompetent. 

Memory:  Also, according to Rule 603, witnesses must be able to recall and relate the events they are testifying about.

Witness Refusing Oath: In a federal criminal case involving embezzlement charges, a key witness, upon taking the stand, refuses to take the oath or affirm to testify truthfully, as required by Rule 603.  Their refusal renders them incompetent to testify. 

Lack of Personal Knowledge: In a federal conspiracy case, the cousin of one of the co-conspirators is asked to testify to the alleged conspiracy.  The cousin has no personal knowledge of the conspiracy and has not spoken to her cousin, the defendant, in 20 years.  This witness’s lack of personal knowledge may render her incompetent under Rule 602. 

If you have been charged a crime, it is critical that you discuss your case immediately with a knowledgeable and aggressive criminal defense attorney as soon as possible.  As a former Deputy District Attorney with over 14 years of prosecutorial experience, Los Angeles criminal defense attorney Michael Kraut has a vast knowledge of witness competency in both California and federal cases. 

For more information about the criminal justice process, and to schedule your free consultation, contact Michael Kraut at the Kraut Law Group located at 6255 Sunset Boulevard, Suite 1520, Los Angeles, CA 90028.  Mr. Kraut can be reached 24/7 at (888) 334-6344 or (323) 464-6453.