From: Rabbi Moshe Sofer
To: Unknown recipient
A Jewish soldier named Leibel Shmuel had been missing for years; his father-in-law R' Daniel obtained a military officer's letter, an official Totenschein from the General Command, and the incidental testimony of R' Shemayah of Banovitz who noticed Leibel's name erased from the military register. The Chasam Sofer rules the wife is permitted to remarry, relying primarily on the reliability of governmental records (erchaos) for agunah cases, resolving objections regarding the Totenschein's status as non-mesiach-l'fi-tumo and non-Jewish written testimony, and ultimately finding that the officer's letter itself qualified as mesiach l'fi tumo since R' Daniel had written asking about a substitute soldier rather than directly about his son-in-law's fate.
Source: Shu"t Chasam Sofer EH I §43