In most circumstances, text messages and other written communications – such as private messages and emails – are admissible as evidence during a child custody case in California. The family courts will only admit text messages as evidence, however, if the messages were obtained legally. The text messages must be relevant to the case and authenticated. This means that it must be proven that the spouse sent the text messages. The messages also must not have been obtained illegally, such as with stolen passwords or hacking. This is the only way that text messages will be permitted as evidence in a custody case.