The only theory that makes close to any sense is that the brother had behavior problems the family kept behind closed doors that led to the brother injuring jonbenet in a little brother/sister dispute they the night before she was found dead, leading to her death. And when the parents found out what happened, they staged jonbenet’s body in the basement, the mother wrote the ransom note and acted like they were being targeted to cover the whole thing up to avoid ridicule from the public about their son. But that is just a theory.