The Thumb Mark of St. Peter
Miss Marple's niece, Mabel, married a violent man who later died suddenly, and the village gossips think that Mabel murdered him. From The Thirteen Problems.
More about this story
Mabel, a niece of Miss Marple, is accused of the murder of her violent husband, whose family has a history of insanity. When arsenic is found in the house Mabel claims to have been intended to commit suicide, but who is telling the truth? The Tuesday Night Club attempt to resolve the mystery, the only story Marple tells them.
In this story Miss Marple describes what may have been the very first murder she solved. The story was published in the Royal Magazine in the UK in 1928. It was included in the 1932 collection, The Thirteen Problems, Miss Marple's first short story collection.
Elements of the story were woven into the plot of the episode Greenshaw's Folly as part of series six of Agatha Christie's Marple, which aired in the UK in 2013. Julia McKenzie was Miss Marple.