Agatha Christie 
Thumb Mark of St. Peter [PDF ebook] 

The Thumb Mark of St. Peter is a short story written by the talented Agatha Christie. At one meeting of the Tuesday Night Club, Miss Marple tells how she helped her niece Mabel to prove her innocence when she was wrongly accused of her husband’s murder. Agatha Christie proves once again that her detectives are very wise, both professional and amateur, and that she knows human nature deeply.