Task: Question Answering
Input (English): Passage: Mikey, a young boy, is setting newspapers on fire in his basement. He blames his younger sister, Beth, when his foster mother, Grace, reprimands him for it. Grace slaps him, and he later yells at Beth, asking her why she didn't defend him. He ends up throwing her doll into the pool. When Beth reaches to get it, Mikey jumps up and down on the diving board, causing her to fall into the pool and drown.
He goes upstairs to the bathroom, where he overhears Grace taking a bath and telling a friend on the phone that adopting Mikey might have been a mistake. The phone dies, and Grace notices Mikey standing in front of the tub. Startled, she chides him for not knocking before he came in. He accuses Grace and Harold of not loving him anymore, but she denies that, saying they both love him very much. However, Mikey doesn't believe her; he picks up her blow dryer, turns it on, and begins to taunt her. He throws it into the water and she is instantly electrocuted.
Mikey goes downstairs and pours marbles onto the floor. When his foster father Harold arrives home, he calmly goes to greet him. They sit and talk for a moment until Harold sees his daughter floating lifelessly in the pool. He rushes towards the door, but slips on the marbles Mikey had laid down earlier. After Harold crashes through the door panel, Mikey proceeds to kill him by beating him in the head with a baseball bat. It is then revealed that Mikey has been taping the murders in secret. Soon after that, the police have arrived to investigate the murders and they finally finds Mikey "hiding" in a closet. He tells them a man came in and killed his family.
A psychiatrist recommends that Mikey be fostered as soon as possible. His foster mother's sister is put forward as a prospective foster carer, but she does not want anything to do with Mikey. She states that he was adopted, and that it was suspected that he was abused by members of his family. 
Question: Who does Mikey beat with a baseball bat?
Output (English): Harold.