Legal Question in Native American Law in California

In United States courts, state and federal, no one who is competent to testify can refuse to be called and questioned as a witness. Indeed, it may require the taking of testimony and the admission of evidence before the judge and jury can know who is the victim (although often it's pretty obvious, it isn't always). In tribal courts, it would depend upon the tribe's own law, but I'd say most would not excuse someone from appearing as a witness on the basis that they were the victim. Often, proof in a civil or criminal matter absolutely depends upon the testimony of the alleged victim.