The below letter to Mr and Mrs Thorsten Ellingson appears to be missing a page. They are informed that their son's remains are non-recoverable.

Next is a formal document signed by Christine Hayden, who may have written the letter , followed by a STATEMENT OF INVESTIGATION
also signed by her.

Documents in Page 2 provide information on why some remains from the Tokyo Prison Fire, including those who were assigned X numbers and tentatively identified, are considered to be non-recoverable.

SSgt Ellingson's Report of Death ( in Official Documents ) states the cause as Killed in Action. There is nothing to indicate that he was a POW nor that his remains were not recoverable.

My preferred wording is:
Killed in Action - Remains Not Recoverable