Muriel was the younger sister of the famous Amelia. She was among other things a teacher and writer, and penned two books (long after Amelia was gone) on her (Courageous sister)- indeed the title of...
No one can answer that because her death is a mystery that no one can figure out. She suspectedly died because her plane got jammed and crashed into the ocean. but as i said no one knows about her...