Bava Batra 158a בבא בתרא קנ״ח א

MISHNA: If the house collapsed upon a husband and upon his wife, and it is unknown who died first, if the wife did not have any children from her husband, then the following claims arise: The husband’s heirs say: The wife died first and was inherited by her husband, and afterward the husband died, and therefore the husband’s heirs inherit both his and her property. The wife’s heirs say: The husband died first and afterward the wife died, and her heirs inherit the property that she brought with her to the marriage and the payment of her marriage contract.

Beit Shammai say: They divide the property under dispute between them. And Beit Hillel say: The guaranteed property that the wife brought with her to the marriage retains its previous ownership status. The sum of the marriage contract remains in the possession of the husband’s heirs, since the marriage contract is collected from the husband’s property. Property that is brought into and taken out of the marriage with her, i.e., usufruct property that remains in the wife’s possession during her marriage, remains in the possession of the heirs of the woman’s father.