Tosefta for Bava Batra 283:3
אמר רב ששת מנא אמינא לה דתניא גר שמת ובזבזו ישראל נכסיו ושמעו שיש לו בן או שהיתה אשתו מעוברת חייבין להחזיר החזירו הכל ואחר כך שמעו שמת בנו או שהפילה אשתו החזיק בשניה קנה ובראשונה לא קנה
If a proselyte died<span class="x" onmousemove="('comment',' And, having left no children, his possessions become public property, and whosoever takes possession of them acquires ownership. ');"><sup>8</sup></span> and Israelites plundered his estate; and [subsequently] they heard that he had a son or that his wife was pregnant. they must return [whatever they have appropriated].<span class="x" onmousemove="('comment',' Since the son or the embryo. as legal heir. acquired the ownership of the estate as soon as the proselyte died. ');"><sup>9</sup></span> [If]. having returned everything they subsequently heard that his son died or that his wife miscarried, he who took possession the second [time]<span class="x" onmousemove="('comment',' After the death of the son or the miscarriage. ');"><sup>10</sup></span> has acquired ownership;<span class="x" onmousemove="('comment',' Since at that time there were no legal heirs ');"><sup>11</sup></span> but [he who took possession] the first [time] has not acquired ownership. Now, if it could be assumed [that] an embryo does not acquire ownership why should they<span class="x" onmousemove="('comment',' In the case where there was no born son, but an embryo. ');"><sup>12</sup></span>