"And I do want to know about this mysterious letter."

He laid aside the record and picked up his father's mysterious letter.

Both received mysterious letters from Washington asking about their knowledge of foreign languages.

He keeps wondering about a mysterious letter she received one Sunday long past.

Their lives are controlled by orders set out in a mysterious letter.

Why is this mysterious letter to be sent to Philip's father?

The mysterious letter must be to do with their son.

"This mysterious letter was written in "the season of Easter.

Perhaps these mysterious letters are worth a great deal of money, yes?

She received a mysterious letter warning her to be careful.