The Gun in Betty Lou's Handbag

Betty Lou Perkins is a meek librarian in New Orleans who nobody pays much attention to, in particular her husband, Alex. A criminal kingpin is killed in cold blood and Betty Lou happens to find the murder gun. She is so mousy, however, she cannot even get the police to listen to her, including Alex, who is a detective. In sheer frustration, she not only produces the gun but also announces she is the one who committed the crime.