In a news story that broke on February 8, a former California high school administrator is now at the center of three (3) separate lawsuits charging that the school district was negligent in hiring Andrea Cardosa, who is accused of engaging in inappropriate sexual behavior with these girls, more specifically, "grooming" them for her advances.
"So, how is the school district responsible for that?" you ask.
Andrea Cardosa following her arraignment
If you give credence to the lawsuits' claims, it appears that Ms. Cardosa had a history of sexual misconduct involving students, but this history was swept under the rug by her former school district in exchange for her voluntarily resigning her position and then moving to a different school district. In other words, the (new) school district failed to do its due diligence before hiring Ms. Cardosa, and thereby put these children unnecessarily at risk.
Assuming the truth of these allegations (and there is a companion criminal case charging Ms. Cardosa with numerous felony counts), this is the paradigm of how you prove a negligent hiring case against a school district.