From: Rabbi Moshe Sofer
To: Rabbi Ber
A woman sought to remarry after her husband was listed as dead in official military death registers. The Chasam Sofer concludes that if a Jew personally saw the entry in the military death register with no concern about name confusion, the woman is certainly permitted to remarry; if no Jew saw it directly but a death certificate bearing an official government seal was obtained, this too can serve as a basis for leniency. He declines to issue a final ruling without formal submission of the case and the missing details.
Source: Shu"t Chasam Sofer EH I §44