what happened after man from Nepal sent certified mail to his Ambassador in Washington DC?

May 2014:  Mr. N, from Nepal, suffered no physical harm in his country.
He came to USA, and wrote a letter of complaint and criticism to the Nepal ambassador, who has an office in Washington DC.  He sent the letter by certified mail, attaching PS Form 3811 to the envelope.

PS Form 3811 is green, and is about the same size as a post card. It goes to the address, and someone there signs it, and gives it back to the Post Office. The Post Office then sends it to the man who wrote the letter.

The asylum officer asked, "Did the ambassador actually receive your letter?"
Mr. N showed the signed PS Form 3811 to the officer.

He was granted asylum.[Arlington Asylum Office, May 2014]