i have been trying to find this movie for years! I say it sometime in the 90s on tv. It was about a teenage girl that became best friends with the girl across the road. She became obsessed and hated her parents so she closed there bedroom door and poured gasoline in front of the door (while her parents where sleeping in bed) and lit it on firer which ended up killing them. Then her best friends parents let her stay with them and close to the end of the movie both of the girls get into a physical fight and smashes the girls head into a sprinkler head. That’s all I can remember could be a 1980s video not sure hope someone can help me out!