She was poison for him

He was recovering from drug abuse, he just wanted to move on with his life. But that was before he met her. She was a good girl with a little bit of a wild side. They began hanging out, and he started to really like her alot. Her parents didn't like him because of his past. So she thought up a plan so that she could stay with him. She wanted him to kill her parents so they could be together for good. When she told him her plan he was wary but he knew he wanted to be with her so he agreed. They planned it out together, and when it came down to that day they waited until nightfall.Then when it was night he crept into the house, and shot them both. Then when questions started coming she told them that it was him who killed her parents. When he was arrested he knew she was poison for him.