In Khaled Hosseini's A Thousand Splendid Suns, Mariam kills Rasheed after Rasheed attacks and almost kills Laila. Rasheed is a violent, abusive man who is married to both of these women. Mariam is married to him when she is only a girl. She has no choice in the matter, for her father arranges the marriage. Rasheed has strict rules for his new wife, and he is disappointed when she does not conceive a child. He punishes Mariam in many different ways when she makes mistakes, even making her chew on pebbles.
Years pass, and Mariam and Rasheed take in a girl named Laila, whose family is killed in a rocket attack. Rasheed marries Laila against Mariam's wishes, and at first there is plenty of tension between the two women. When Laila gives birth to a daughter (to Rasheed's disgust), however, Mariam and Laila bond over the baby, and they grow to be very close.
Rasheed becomes more and more violent toward both of his wives. Laila's beloved Tariq returns, and Rasheed finds out that Laila is communicating with him. Rasheed is furious, and he beats Laila with his belt. As his fury rises, Rasheed then attacks Laila even more vigorously. Mariam knows that he means to kill Laila, so she grabs a shovel and hits Rasheed on the head. He falls down dead. Mariam has killed Rasheed, but she will not run. She knows she will be caught.
Laila and Tariq take Laila's two children and flee. Mariam goes to prison and is executed for her deed.