1) Your mother can press charges for identity theft (the exact name of the crime will vary state-by-state, but pretending to be another person is always a crime) and also for theft (stealing the ashes, even if done by trickery).2) If she is engaged in a pattern of harassment, that may also be a crime--you can discuss that with the police while bringing the above to their attention.3) You can sue for a court order that the ashes be returned, but you have to do this in "regular" court, not small claims--small claims cannot issue orders like that--which will increase the cost and complexity. The executor/personal representative would do this.