Write a letter to a stranger, thanking him for returning your parcel, which you had left behind in the train.

32-Lal Bagh, 

Saharanpur,

21st April 19...... 


Dear Mr. XYZ,

Please accept my heartfelt gratitude, for safely returning the parcel that I had in my haste left behind in the train.

You have relieved me of great tension that I was under since the loss of the document. The parcel contained some legal documents which had an immense bearing in a lawsuit about a property dispute.

Sir, I once again thank you for your kind act. 

With regards, 

Yours, sincerely 

Mehra.