If you had a child that murdered everyone in your entire family except you, could you forgive him or her and still carry a relationship with him or her?

I am watching a documentary on Killer Women, and one of the women they are talking about is this 24 year old woman, Erin. Erin was seen as a nice Christian Texan girl. She came from a Christian and loving home where no abuse took place. They even bought her a car and helped her work. One thing her parents always did though was make her break up with her boyfriends. Well after the parents made her break up with her last boyfriend, she conspired to have him and a couple of his friends kill her entire family. She was 16 at the time. She sat in the car as her boyfriend and his friends went inside her home and shot and stabbed to death her mother and two brothers (about eight and twelve). They also shot the dad, but he ended up living. Then they set the entire house on fire and burned it to the ground. Afterwards, she went back to her boyfriend's place and had sex with him like nothing happened. It is known that the murder plot was Erin's idea, and she was the Mastermind. Despite this, her dad has forgiven her and continues a relationship with her. My question is if this was your child, could you forgive him or her? Could you continue a relationship with someone who has done something so horrible?