In order to prove that a fraud has occurred there must be proof of an intent to deceive. For example, in order to prove that false representations were made to a testator in the Estate of Newhall, two of the testator's daughters made false statements about a third daughter and falsely claimed that the third daughter was immoral and had initiated a guardianship proceeding against the testator. The Newhall Court held that it was for the trier of fact to determine whether these misrepresentations had induced the testator to disinherit the third daughter. Estate of Newhall (1923) 190 Cal. 709, 214-231
If you believe someone has been the victim of fraud or undue influence you should consult with a California probate attorney to discuss your options.