Generate a question that has the following answer: Norman Stansfield for the following movie plot: Leon Montana (Jean Reno) is an Italian hitman (or "cleaner", as he refers to himself) living a solitary life in New York City's Little Italy. His work comes from a mafioso named Tony (Danny Aiello). Leon spends his idle time engaging in calisthenics, nurturing a houseplant, and watching old films. One day, Leon sees Mathilda Lando (Natalie Portman), a twelve-year-old girl who is smoking a cigarette and sporting a black eye. Mathilda lives with her dysfunctional family in an apartment down the hall. Her abusive father and self-absorbed stepmother have not noticed that Mathilda stopped attending class at her school for troubled girls. Mathilda's father (Michael Badalucco) attracts the ire of corrupt DEA agents, who have been paying him to stash cocaine in his apartment. After they discover he has been cutting the cocaine to keep some for himself, DEAagents storm the building, led by sharply dressed drug addict Norman Stansfield (Gary Oldman). During the raid, Stansfield quickly becomes unhinged and murders Mathilda's entire family one by one while Mathilda is out shopping. When Mathilda returns, she realizes what has happened just in time to continue down the hall, where she desperately knocks on her neighbour's door. A hesitant Leon gives her shelter. Mathilda quickly discovers that Leon is a hitman. She begs him to take care of her and to teach her his skills, as she wants to avenge the murder of her four-year-old brother. At first, Leon is unsettled by her presence. He even almost kills her in her sleep, possibly out of mercy, but can't bring himself to do it. The next morning, Leon tries to throw Mathilda out, but she claims that, because he saved her life the previous day, he is now responsible for her, stating that she would be dead by the end of the day if he threw her out and it would be like he had never opened the door for her. She begs him to train her as a "cleaner," demonstrating her willingness to learn by taking Leon's gun and firing randomly onto the street outside his open window....
A:
Who killed Mathilda's family?