Historical question about (alleged) motive

I recently watched this series on Netflix and read a few posts about it. I don't particularly care for gorefest but, beyond that, I am curious why/how historians ascertained that Lizzie was NOT molested by her father and stepmother. Does anyone have any recommendations for good books or research on this subject?

I am hesitant to believe the "official" story simply because of the nature of that particular type of abuse and how prevalent it STILL is for people to deny and/or blame the victim while the perpetrators can usually go on for years (or decades, in some cases) without ever being questioned; let alone, arrested and charged with such crimes. It was even less likely for the police to do anything if the accusers were female. Sadly, that is still very much the case. I'm not suggesting she should be believed simply because she (or her defense) says so, but to dismiss it out of turn seems very symptomatic of our society's unwillingness to accept that NOT ALL parents are loving, kind and nurturing and all children aren't evil, ungrateful b*stards that just don't know how to "forgive and forget."

- Get busy living, or get busy dying. Andy (The Shawshank Redemption)