1,858. One Who Dies on a Journey or in Captivity
Hilchos Geirushin 13:25
Let’s say that a Jew and a non-Jew departed on a journey together. The non-Jew later returns and says in the course of normal conversation that the Jew who left with him died. The wife of the deceased may remarry based on this testimony. This is so even if the non-Jew doesn’t know the deceased so long as he says that he buried him.
Hilchos Geirushin 13:26
The same is true if ten men were taken away in chains or tied by heavy ropes like those used to lead camels. If a non-Jew arrived, reporting in the course of normal conversation that all ten died and he buried them, their wives may remarry based on his words.