No, a recorded voice message is NOT legally binding in terms of determining who receives property after someone passes away. Only a written will, properly signed and executed in accordance with the laws of the state where the decedent (person passing away) lived when he created the will controls what happens to his property/assets. Any other writing or any oral message or instructions, including one that was recorded, has no legal effect whatsoever. The rest of the family could take legal action--they could try reporting this to the police, but the police might improperly consider this a civil dispute, not theft and refuse to help; they could also file a lawsuit for the recovery of this property or for its economic value. (More technically, whomever is appointed the estate's administrator or personal representative by the probate court could file a lawsuit on behalf of the estate.)