Expanding when may a witness testify that the husband is dead TB Yevamot 120

What are the circumstances that permitted a witness to testify that the man is dead? “One may testify that a man died only if he can testify about seeing the countenance [partzuf ] of the face with the nose, as this allows one to identify the individual with certainty. Although there are distinguishing marks [simanim] on his body and his personal belongings, which appear to indicate his identity, one may not rely on these as identification. Furthermore, one may not testify that a person died until his soul actually departs. And even if one saw him cut open and severely wounded, or crucified, or with a wild animal eating parts of him, he may not testify that he died. Additionally, one may testify to someone’s death only when the body was witnessed up to three days following death and not after that, since the appearance may change due to decomposition.

Rabbi Yehuda ben Bava says: One cannot establish general guidelines for this matter because not every person, nor every place, nor every hour is identical. Decomposition is not uniform. It occurs at different rates in different situations.” (Sefaria.org translation)

Even though the Mishnah limits the circumstances when a person is permitted to testify concerning the death of another person, Gemara and Tosefot expand the opportunities to testify. This is important in the cases of levirate marriage for these expansions allows a widow to marry a yavam or anybody else depending on her circumstances. For example “The Gemara answers: The mishna’s intent (prohibiting the reliance of distinguishing marks as means of indemnification ) is that ordinary distinguishing marks on one’s body, which constitute only weak evidence to a person’s identity, e.g., that he was tall or short, are not valid identification.” (Sefaria.org translation) For example somebody could identify my body by seeing my misshapen left thumb because of my bicycle accident.

Tosefot ד"ה אֵין מְעִידִין אֶלָּא עַל פַּרְצוּף פָּנִים עִם הַחוֹטֶם commenting on “One may testify that a man died only if he can testify about seeing the countenance [partzuf ] of the face with the nose” writes: Rebbeinu Tam says this ruling applies when the countenance of the face and the nose are the only body parts left of the deceased. However if the whole body is complete even without a forehead and nose the deceased can be identified very well by the distinguishing body marks. Tosefot continues that even after three days it could be possible to identify a body because of its distinguishing marks.