Mr. Beale knew Maniac was homeless because when he was driving Maniac home, Maniac lied that his house was the house in front of the car. Mr. Beale knew Maniac was lying so Maniac explained that he was running away and was homeless.
A maniac is a person who acts crazy or dangerous. Here are some sentences. You are behaving like a maniac today! The maniac escaped from the mental institution and went on a rampage. She's dancing like a maniac.