When a person drowned in a body of water that has no end, and witnesses testify that he drowned in their presence and all traces of him were lost, his heirs may inherit his estate on the basis of their testimony, despite the fact that, at the outset, his wife is not permitted to remarry in this situation.
Similarly, if witnesses come and testify that they saw a person fall into a lions' or tigers' den, they saw him crucified with birds eating from his body, he was pierced in battle and died, or he was killed, but his face was not recognizable, but there were definitive signs on his body and they were identified - with regard to these and similar situations, if all traces of the person were lost afterwards, the heirs may assume possession of the inheritance because of such testimony, although the person's wife is not given license to marry.
I maintain that our Sages were stringent concerning these matters only because of the severity of the prohibition involving karelt involved. With regard to financial matters, by contrast, if witnesses testify with regard to matters that we can presume will lead to death, saying that they saw these matters, all traces of the person are lost, and afterwards it is heard that he died, we allow the heirs to assume possession of the estate on this basis. This is the standard practice followed on an everyday basis in all courts of law. We have not heard about anyone who rules differently regarding this matter.